Vulnerability · Published Aug 13, 2026 · Assigned by Go

CVE-2026-56858Fix Javascript regexp context tracking in html/template

Medium 6.1

In plain English

A medium-severity cross-site scripting in html/template from Go standard library. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 24% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)6.1Medium
Exploit odds (30 days)0.3%top 76.1% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

Previously, pathological inputs could close an unescaped '/' early, allowing for attack-controlled data to inject arbitrary content, potentially leading to XSS.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
AlmaLinux:8aardvark-dns2:1.10.1-2.module_el8.10.0+3909+6e1c1eb7ALSA-2026:63163
AlmaLinux:8aardvark-dns2:1.10.1-2.module_el8.10.0+3901+4b80ecd7ALSA-2026:63163
AlmaLinux:8aardvark-dns2:1.10.1-2.module_el8.10.0+4047+545787c4ALSA-2026:63163
AlmaLinux:8aardvark-dns2:1.10.1-2.module_el8.10.0+4023+db236c53ALSA-2026:63163
AlmaLinux:10buildah2:1.43.1-5.el10_2ALSA-2026:63332
AlmaLinux:10buildah2:1.43.1-6.el10_2ALSA-2026:64777
AlmaLinux:8buildah2:1.33.14-6.module_el8.10.0+4269+94686149ALSA-2026:63163
AlmaLinux:9buildah2:1.43.3-2.el9_8ALSA-2026:70640
AlmaLinux:10buildah-tests2:1.43.1-5.el10_2ALSA-2026:63332
AlmaLinux:10buildah-tests2:1.43.1-6.el10_2ALSA-2026:64777
AlmaLinux:8buildah-tests2:1.33.14-6.module_el8.10.0+4269+94686149ALSA-2026:63163
AlmaLinux:9buildah-tests2:1.43.3-2.el9_8ALSA-2026:70640
AlmaLinux:8cockpit-podman84.1-1.module_el8.10.0+4102+6c76e544ALSA-2026:63163
AlmaLinux:8conmon3:2.1.10-1.module_el8.10.0+3970+8445edf6ALSA-2026:63163
AlmaLinux:8conmon3:2.1.10-1.module_el8.10.0+3845+87b84552ALSA-2026:63163
AlmaLinux:8container-selinux2:2.229.0-3.module_el8.10.0+4213+0493256bALSA-2026:63163
AlmaLinux:8containernetworking-plugins1:1.4.0-10.module_el8.10.0+4269+94686149ALSA-2026:63163
AlmaLinux:9containernetworking-plugins1:1.9.0-4.el9_8ALSA-2026:70391
AlmaLinux:8containers-common2:1-82.module_el8.10.0+4089+ce72bbbeALSA-2026:63163
AlmaLinux:8containers-common2:1-82.module_el8.10.0+4120+03ad4b47ALSA-2026:63163
AlmaLinux:8containers-common2:1-82.module_el8.10.0+4068+0e21408fALSA-2026:63163
AlmaLinux:8containers-common2:1-82.module_el8.10.0+4016+efd18bf8ALSA-2026:63163
AlmaLinux:8crit3.18-5.module_el8.10.0+4047+545787c4ALSA-2026:63163
AlmaLinux:8crit3.18-5.module_el8.10.0+3845+87b84552ALSA-2026:63163
AlmaLinux:8crit3.18-5.module_el8.10.0+4120+03ad4b47ALSA-2026:63163
AlmaLinux:8crit3.18-5.module_el8.10.0+3901+4b80ecd7ALSA-2026:63163
AlmaLinux:8criu3.18-5.module_el8.10.0+3970+8445edf6ALSA-2026:63163
AlmaLinux:8criu3.18-5.module_el8.10.0+3845+87b84552ALSA-2026:63163
AlmaLinux:8criu3.18-5.module_el8.10.0+3876+e55593a8ALSA-2026:63163
AlmaLinux:8criu3.18-5.module_el8.10.0+4120+03ad4b47ALSA-2026:63163
AlmaLinux:8criu-devel3.18-5.module_el8.10.0+4016+efd18bf8ALSA-2026:63163
AlmaLinux:8criu-devel3.18-5.module_el8.10.0+4068+0e21408fALSA-2026:63163
AlmaLinux:8criu-devel3.18-5.module_el8.10.0+4089+ce72bbbeALSA-2026:63163
AlmaLinux:8criu-devel3.18-5.module_el8.10.0+4082+f7f0c95eALSA-2026:63163
AlmaLinux:8criu-libs3.18-5.module_el8.10.0+3970+8445edf6ALSA-2026:63163
AlmaLinux:8criu-libs3.18-5.module_el8.10.0+3909+6e1c1eb7ALSA-2026:63163
AlmaLinux:8criu-libs3.18-5.module_el8.10.0+4082+f7f0c95eALSA-2026:63163
AlmaLinux:8criu-libs3.18-5.module_el8.10.0+4068+0e21408fALSA-2026:63163
AlmaLinux:8crun1.14.3-4.module_el8.10.0+4269+94686149ALSA-2026:63163
AlmaLinux:8delve1.26.1-1.module_el8.10.0+4223+bd807c2eALSA-2026:60305
AlmaLinux:8fuse-overlayfs1.13-1.module_el8.10.0+3970+8445edf6ALSA-2026:63163
AlmaLinux:8fuse-overlayfs1.13-1.module_el8.10.0+4082+f7f0c95eALSA-2026:63163
AlmaLinux:8fuse-overlayfs1.13-1.module_el8.10.0+4068+0e21408fALSA-2026:63163
AlmaLinux:8fuse-overlayfs1.13-1.module_el8.10.0+3909+6e1c1eb7ALSA-2026:63163
AlmaLinux:10go-toolset1.26.7-1.el10_2.alma.1ALSA-2026:60306
AlmaLinux:8go-toolset1.26.7-1.module_el8.10.0+4264+117c8fc2ALSA-2026:60305
AlmaLinux:9go-toolset1.26.7-1.el9_8ALSA-2026:60304
AlmaLinux:10golang1.26.7-1.el10_2.alma.1ALSA-2026:60306
AlmaLinux:8golang1.26.7-1.module_el8.10.0+4264+117c8fc2ALSA-2026:60305
AlmaLinux:9golang1.26.7-1.el9_8ALSA-2026:60304
AlmaLinux:10golang-bin1.26.7-1.el10_2.alma.1ALSA-2026:60306
AlmaLinux:8golang-bin1.26.7-1.module_el8.10.0+4264+117c8fc2ALSA-2026:60305
AlmaLinux:9golang-bin1.26.7-1.el9_8ALSA-2026:60304
AlmaLinux:10golang-docs1.26.7-1.el10_2.alma.1ALSA-2026:60306
AlmaLinux:8golang-docs1.26.7-1.module_el8.10.0+4264+117c8fc2ALSA-2026:60305
AlmaLinux:9golang-docs1.26.7-1.el9_8ALSA-2026:60304
AlmaLinux:10golang-misc1.26.7-1.el10_2.alma.1ALSA-2026:60306
AlmaLinux:8golang-misc1.26.7-1.module_el8.10.0+4264+117c8fc2ALSA-2026:60305
AlmaLinux:9golang-misc1.26.7-1.el9_8ALSA-2026:60304
AlmaLinux:10golang-race1.26.7-1.el10_2.alma.1ALSA-2026:60306
AlmaLinux:8golang-race1.26.7-1.module_el8.10.0+4264+117c8fc2ALSA-2026:60305
AlmaLinux:9golang-race1.26.7-1.el9_8ALSA-2026:60304
AlmaLinux:10golang-src1.26.7-1.el10_2.alma.1ALSA-2026:60306
AlmaLinux:8golang-src1.26.7-1.module_el8.10.0+4264+117c8fc2ALSA-2026:60305
AlmaLinux:9golang-src1.26.7-1.el9_8ALSA-2026:60304
AlmaLinux:10golang-tests1.26.7-1.el10_2.alma.1ALSA-2026:60306
AlmaLinux:8golang-tests1.26.7-1.module_el8.10.0+4264+117c8fc2ALSA-2026:60305
AlmaLinux:9golang-tests1.26.7-1.el9_8ALSA-2026:60304
AlmaLinux:10grafana10.2.6-28.el10_2.5ALSA-2026:63022
AlmaLinux:8grafana9.2.10-33.el8_10ALSA-2026:62407
AlmaLinux:9grafana10.2.6-23.el9_8.3ALSA-2026:62406
AlmaLinux:10grafana-pcp5.3.0-8.el10_2.1ALSA-2026:63119
AlmaLinux:8grafana-pcp5.1.1-18.el8_10ALSA-2026:63124
AlmaLinux:9grafana-pcp5.1.1-17.el9_8.1ALSA-2026:63136
AlmaLinux:10grafana-selinux10.2.6-28.el10_2.5ALSA-2026:63022
AlmaLinux:8grafana-selinux9.2.10-33.el8_10ALSA-2026:62407
AlmaLinux:9grafana-selinux10.2.6-23.el9_8.3ALSA-2026:62406
AlmaLinux:8libslirp4.4.0-2.module_el8.10.0+4090+91932338ALSA-2026:63163
AlmaLinux:8libslirp4.4.0-2.module_el8.10.0+4120+03ad4b47ALSA-2026:63163
AlmaLinux:8libslirp4.4.0-2.module_el8.10.0+4068+0e21408fALSA-2026:63163
AlmaLinux:8libslirp4.4.0-2.module_el8.10.0+4016+efd18bf8ALSA-2026:63163
AlmaLinux:8libslirp-devel4.4.0-2.module_el8.10.0+4082+f7f0c95eALSA-2026:63163
AlmaLinux:8libslirp-devel4.4.0-2.module_el8.10.0+3970+8445edf6ALSA-2026:63163
AlmaLinux:8libslirp-devel4.4.0-2.module_el8.10.0+4102+6c76e544ALSA-2026:63163
AlmaLinux:8libslirp-devel4.4.0-2.module_el8.10.0+4068+0e21408fALSA-2026:63163
AlmaLinux:8netavark2:1.10.3-1.module_el8.10.0+4023+db236c53ALSA-2026:63163
AlmaLinux:8netavark2:1.10.3-1.module_el8.10.0+3926+f12484f5ALSA-2026:63163
AlmaLinux:8netavark2:1.10.3-1.module_el8.10.0+4082+f7f0c95eALSA-2026:63163
AlmaLinux:8netavark2:1.10.3-1.module_el8.10.0+4047+545787c4ALSA-2026:63163
AlmaLinux:8oci-seccomp-bpf-hook1.2.10-3.module_el8.10.0+4269+94686149ALSA-2026:63163
AlmaLinux:10opentelemetry-collector0.152.1-2.el10_2ALSA-2026:65116
AlmaLinux:9opentelemetry-collector0.152.1-2.el9_8ALSA-2026:65117
AlmaLinux:8osbuild-composer101.5-2.el8_10.alma.1ALSA-2026:66016
AlmaLinux:9osbuild-composer165.1-4.el9_8.1.alma.1ALSA-2026:65153
AlmaLinux:8osbuild-composer-core101.5-2.el8_10.alma.1ALSA-2026:66016
AlmaLinux:9osbuild-composer-core165.1-4.el9_8.1.alma.1ALSA-2026:65153
AlmaLinux:8osbuild-composer-worker101.5-2.el8_10.alma.1ALSA-2026:66016
AlmaLinux:9osbuild-composer-worker165.1-4.el9_8.1.alma.1ALSA-2026:65153
AlmaLinux:10podman7:5.8.2-9.el10_2.alma.1ALSA-2026:70201
AlmaLinux:8podman4:4.9.4-37.module_el8.10.0+4269+94686149ALSA-2026:63163
AlmaLinux:9podman6:5.8.2-7.el9_8ALSA-2026:69961
AlmaLinux:8podman-catatonit4:4.9.4-37.module_el8.10.0+4269+94686149ALSA-2026:63163
AlmaLinux:10podman-docker7:5.8.2-9.el10_2.alma.1ALSA-2026:70201
AlmaLinux:8podman-docker4:4.9.4-37.module_el8.10.0+4269+94686149ALSA-2026:63163
AlmaLinux:9podman-docker6:5.8.2-7.el9_8ALSA-2026:69961
AlmaLinux:8podman-gvproxy4:4.9.4-37.module_el8.10.0+4269+94686149ALSA-2026:63163
AlmaLinux:8podman-plugins4:4.9.4-37.module_el8.10.0+4269+94686149ALSA-2026:63163
AlmaLinux:9podman-plugins6:5.8.2-7.el9_8ALSA-2026:69961
AlmaLinux:10podman-remote7:5.8.2-9.el10_2.alma.1ALSA-2026:70201
AlmaLinux:8podman-remote4:4.9.4-37.module_el8.10.0+4269+94686149ALSA-2026:63163
AlmaLinux:9podman-remote6:5.8.2-7.el9_8ALSA-2026:69961
AlmaLinux:10podman-tests7:5.8.2-9.el10_2.alma.1ALSA-2026:70201
AlmaLinux:8podman-tests4:4.9.4-37.module_el8.10.0+4269+94686149ALSA-2026:63163
AlmaLinux:9podman-tests6:5.8.2-7.el9_8ALSA-2026:69961
AlmaLinux:8python3-criu3.18-5.module_el8.10.0+3901+4b80ecd7ALSA-2026:63163
AlmaLinux:8python3-criu3.18-5.module_el8.10.0+3858+6ad51f9fALSA-2026:63163
AlmaLinux:8python3-criu3.18-5.module_el8.10.0+4047+545787c4ALSA-2026:63163
AlmaLinux:8python3-criu3.18-5.module_el8.10.0+4120+03ad4b47ALSA-2026:63163
AlmaLinux:8python3-podman4.9.0-3.module_el8.10.0+4016+efd18bf8ALSA-2026:63163
AlmaLinux:8runc4:1.2.9-6.module_el8.10.0+4269+94686149ALSA-2026:63163
AlmaLinux:10skopeo2:1.22.2-5.el10_2ALSA-2026:64818
AlmaLinux:8skopeo2:1.14.6-4.module_el8.10.0+4269+94686149ALSA-2026:63163
AlmaLinux:9skopeo2:1.22.2-8.el9_8ALSA-2026:70641
AlmaLinux:10skopeo-tests2:1.22.2-5.el10_2ALSA-2026:64818
AlmaLinux:8skopeo-tests2:1.14.6-4.module_el8.10.0+4269+94686149ALSA-2026:63163
AlmaLinux:9skopeo-tests2:1.22.2-8.el9_8ALSA-2026:70641
AlmaLinux:8slirp4netns1.2.3-1.module_el8.10.0+4023+db236c53ALSA-2026:63163
AlmaLinux:8slirp4netns1.2.3-1.module_el8.10.0+3901+4b80ecd7ALSA-2026:63163
AlmaLinux:8slirp4netns1.2.3-1.module_el8.10.0+4082+f7f0c95eALSA-2026:63163
AlmaLinux:8slirp4netns1.2.3-1.module_el8.10.0+4047+545787c4ALSA-2026:63163
AlmaLinux:8toolbox0.0.99.5.1-1.module_el8.10.0+4120+03ad4b47ALSA-2026:63163
AlmaLinux:8toolbox-tests0.0.99.5.1-1.module_el8.10.0+4120+03ad4b47ALSA-2026:63163
AlmaLinux:8udica0.2.6-21.module_el8.10.0+4068+0e21408fALSA-2026:63163
Alpine:v3.24go1.26.8-r0ALPINE-CVE-2026-56858
Debian:12golang-1.19no fix listedDEBIAN-CVE-2026-56858
Debian:13golang-1.24no fix listedDEBIAN-CVE-2026-56858
Debian:14golang-1.261.26.6-1DEBIAN-CVE-2026-56858
Debian:14golang-1.271.27~rc3-1DEBIAN-CVE-2026-56858
Gostdlib1.25.13, 1.26.6, 1.27.0-rc.3GO-2026-6091
Rocky Linux:8aardvark-dns2:1.10.1-2.module+el8.10.0+40047+0c0a73f4RLSA-2026:63163
Rocky Linux:8aardvark-dns2:1.10.1-2.module+el8.10.0+1880+8e896d1bRLSA-2026:63163
Rocky Linux:8aardvark-dns2:1.10.1-2.module+el8.10.0+1896+b18fa106RLSA-2026:63163
Rocky Linux:8aardvark-dns2:1.10.1-2.module+el8.10.0+1874+ce489889RLSA-2026:63163
Rocky Linux:8aardvark-dns2:1.10.1-2.module+el8.10.0+40133+32c21f88RLSA-2026:63163
Rocky Linux:8aardvark-dns2:1.10.1-2.module+el8.10.0+1948+4b5cd4a9RLSA-2026:63163
Rocky Linux:8aardvark-dns2:1.10.1-2.module+el8.10.0+2001+6a33db9fRLSA-2026:63163
Rocky Linux:10buildah2:1.43.1-5.el10_2RLSA-2026:63332
Rocky Linux:10buildah2:1.43.1-6.el10_2RLSA-2026:64777
Rocky Linux:9buildah2:1.43.3-2.el9_8RLSA-2026:70640
Rocky Linux:8cockpit-podman0:84.1-1.module+el8.10.0+1948+4b5cd4a9RLSA-2026:63163
Rocky Linux:8cockpit-podman0:84.1-1.module+el8.10.0+1872+2e18eb19RLSA-2026:63163
Rocky Linux:8cockpit-podman0:84.1-1.module+el8.10.0+1874+ce489889RLSA-2026:63163
Rocky Linux:8cockpit-podman0:84.1-1.module+el8.10.0+40133+32c21f88RLSA-2026:63163
Rocky Linux:8cockpit-podman0:84.1-1.module+el8.10.0+1880+8e896d1bRLSA-2026:63163
Rocky Linux:8cockpit-podman0:84.1-1.module+el8.10.0+1825+623b0c20RLSA-2026:63163
Rocky Linux:8cockpit-podman0:84.1-1.module+el8.10.0+2001+6a33db9fRLSA-2026:63163
Rocky Linux:8cockpit-podman0:84.1-1.module+el8.10.0+1843+6892ab28RLSA-2026:63163
Rocky Linux:8cockpit-podman0:84.1-1.module+el8.10.0+40047+0c0a73f4RLSA-2026:63163
Rocky Linux:8cockpit-podman0:84.1-1.module+el8.10.0+1815+5fe7415eRLSA-2026:63163
Rocky Linux:8cockpit-podman0:84.1-1.module+el8.10.0+1896+b18fa106RLSA-2026:63163
Rocky Linux:8conmon3:2.1.10-1.module+el8.10.0+40133+32c21f88RLSA-2026:63163
Rocky Linux:8conmon3:2.1.10-1.module+el8.10.0+1815+5fe7415eRLSA-2026:63163
Rocky Linux:8conmon3:2.1.10-1.module+el8.10.0+40047+0c0a73f4RLSA-2026:63163
Rocky Linux:8conmon3:2.1.10-1.module+el8.10.0+2001+6a33db9fRLSA-2026:63163
Rocky Linux:8conmon3:2.1.10-1.module+el8.10.0+1948+4b5cd4a9RLSA-2026:63163
Rocky Linux:8conmon3:2.1.10-1.module+el8.10.0+1874+ce489889RLSA-2026:63163
Rocky Linux:8conmon3:2.1.10-1.module+el8.10.0+1872+2e18eb19RLSA-2026:63163
Rocky Linux:8conmon3:2.1.10-1.module+el8.10.0+1880+8e896d1bRLSA-2026:63163
Rocky Linux:8conmon3:2.1.10-1.module+el8.10.0+1896+b18fa106RLSA-2026:63163
Rocky Linux:8conmon3:2.1.10-1.module+el8.10.0+1843+6892ab28RLSA-2026:63163
Rocky Linux:8container-selinux2:2.229.0-3.module+el8.10.0+40223+e940a224RLSA-2026:63163
Rocky Linux:9containernetworking-plugins1:1.9.0-4.el9_8RLSA-2026:70391
Rocky Linux:8containers-common2:1-82.module+el8.10.0+40047+0c0a73f4RLSA-2026:63163
Rocky Linux:8containers-common2:1-82.module+el8.10.0+40133+32c21f88RLSA-2026:63163
Rocky Linux:8containers-common2:1-82.module+el8.10.0+1948+4b5cd4a9RLSA-2026:63163
Rocky Linux:8containers-common2:1-82.module+el8.10.0+2001+6a33db9fRLSA-2026:63163
Rocky Linux:8containers-common2:1-82.module+el8.10.0+1843+6892ab28RLSA-2026:63163
Rocky Linux:8containers-common2:1-82.module+el8.10.0+1872+2e18eb19RLSA-2026:63163
Rocky Linux:8containers-common2:1-82.module+el8.10.0+1874+ce489889RLSA-2026:63163
Rocky Linux:8containers-common2:1-82.module+el8.10.0+1880+8e896d1bRLSA-2026:63163
Rocky Linux:8containers-common2:1-82.module+el8.10.0+1896+b18fa106RLSA-2026:63163
Rocky Linux:8criu0:3.18-5.module+el8.10.0+1948+4b5cd4a9RLSA-2026:63163
Rocky Linux:8criu0:3.18-5.module+el8.10.0+40047+0c0a73f4RLSA-2026:63163
Rocky Linux:8criu0:3.18-5.module+el8.10.0+1843+6892ab28RLSA-2026:63163
Rocky Linux:8criu0:3.18-5.module+el8.10.0+1825+623b0c20RLSA-2026:63163
Rocky Linux:8criu0:3.18-5.module+el8.10.0+1880+8e896d1bRLSA-2026:63163
Rocky Linux:8criu0:3.18-5.module+el8.10.0+40133+32c21f88RLSA-2026:63163
Rocky Linux:8criu0:3.18-5.module+el8.10.0+2001+6a33db9fRLSA-2026:63163
Rocky Linux:8criu0:3.18-5.module+el8.10.0+1874+ce489889RLSA-2026:63163
Rocky Linux:8criu0:3.18-5.module+el8.10.0+1815+5fe7415eRLSA-2026:63163
Rocky Linux:8criu0:3.18-5.module+el8.10.0+1896+b18fa106RLSA-2026:63163
Rocky Linux:8criu0:3.18-5.module+el8.10.0+1872+2e18eb19RLSA-2026:63163
Rocky Linux:8delve0:1.26.1-1.module+el8.10.0+40244+e7cb3ff8RLSA-2026:60305
Rocky Linux:8fuse-overlayfs0:1.13-1.module+el8.10.0+40047+0c0a73f4RLSA-2026:63163
Rocky Linux:8fuse-overlayfs0:1.13-1.module+el8.10.0+1815+5fe7415eRLSA-2026:63163
Rocky Linux:8fuse-overlayfs0:1.13-1.module+el8.10.0+40133+32c21f88RLSA-2026:63163
Rocky Linux:8fuse-overlayfs0:1.13-1.module+el8.10.0+1948+4b5cd4a9RLSA-2026:63163
Rocky Linux:8fuse-overlayfs0:1.13-1.module+el8.10.0+1872+2e18eb19RLSA-2026:63163
Rocky Linux:8fuse-overlayfs0:1.13-1.module+el8.10.0+1874+ce489889RLSA-2026:63163
Rocky Linux:8fuse-overlayfs0:1.13-1.module+el8.10.0+1880+8e896d1bRLSA-2026:63163

Affected products (as reported)

VendorProductVersions
Go standard library html/template 0 – before 1.25.131.26.0-0 – before 1.26.61.27.0-0 – before 1.27.0-rc.3

Weakness: CWE-79 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

References