Vulnerability · Published Sep 28, 2026 · Assigned by GitHub_M
CVE-2026-102268PyJWT: Asymmetric-PEM detection bypass: whitespace/line-ending-mutated public keys skip the HS/asymmetric confusion guard
Critical 9.1
In plain English
A critical-severity security flaw in pyjwt from jpadilla. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 15% of all known vulnerabilities). Ready-made attack tooling exists: public proof-of-concept code. Fixed versions are available - upgrade the affected package.
Severity (CVSS 3.1)9.1Critical
Exploit odds (30 days)0.2%top 85.4% of all CVEs
Exploited in the wildNo reportsCISA SSVC: poc
Attack tooling1Public PoC
Official description
PyJWT is a Python implementation of JSON Web Token standards. Prior to 2.14.0, is_pem_format in jwt/utils.py is affected because is_pem_format does not recognize every PEM representation accepted by the cryptography loader. This occurs when an application mixes HMAC and asymmetric algorithms and supplies a mutated public-key PEM as raw key bytes. As a result, HMACAlgorithm.prepare_key treats the unrecognized asymmetric public key as an HMAC secret. Consequently, an attacker who knows the public key can forge authenticated HMAC tokens. This issue is fixed in version 2.14.0.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux:10 | fence-agents-aliyun | 4.16.0-21.el10_2.7 | ALSA-2026:94501 |
| AlmaLinux:9 | fence-agents-aliyun | 4.10.0-110.el9_8.8 | ALSA-2026:94500 |
| AlmaLinux:10 | fence-agents-all | 4.16.0-21.el10_2.7 | ALSA-2026:94501 |
| AlmaLinux:9 | fence-agents-all | 4.10.0-110.el9_8.8 | ALSA-2026:94500 |
| AlmaLinux:10 | fence-agents-amt-ws | 4.16.0-21.el10_2.7 | ALSA-2026:94501 |
| AlmaLinux:9 | fence-agents-amt-ws | 4.10.0-110.el9_8.8 | ALSA-2026:94500 |
| AlmaLinux:10 | fence-agents-apc | 4.16.0-21.el10_2.7 | ALSA-2026:94501 |
| AlmaLinux:9 | fence-agents-apc | 4.10.0-110.el9_8.8 | ALSA-2026:94500 |
| AlmaLinux:10 | fence-agents-apc-snmp | 4.16.0-21.el10_2.7 | ALSA-2026:94501 |
| AlmaLinux:9 | fence-agents-apc-snmp | 4.10.0-110.el9_8.8 | ALSA-2026:94500 |
| AlmaLinux:10 | fence-agents-aws | 4.16.0-21.el10_2.7 | ALSA-2026:94501 |
| AlmaLinux:9 | fence-agents-aws | 4.10.0-110.el9_8.8 | ALSA-2026:94500 |
| AlmaLinux:10 | fence-agents-azure-arm | 4.16.0-21.el10_2.7 | ALSA-2026:94501 |
| AlmaLinux:9 | fence-agents-azure-arm | 4.10.0-110.el9_8.8 | ALSA-2026:94500 |
| AlmaLinux:10 | fence-agents-bladecenter | 4.16.0-21.el10_2.7 | ALSA-2026:94501 |
| AlmaLinux:9 | fence-agents-bladecenter | 4.10.0-110.el9_8.8 | ALSA-2026:94500 |
| AlmaLinux:10 | fence-agents-brocade | 4.16.0-21.el10_2.7 | ALSA-2026:94501 |
| AlmaLinux:10 | fence-agents-cisco-mds | 4.16.0-21.el10_2.7 | ALSA-2026:94501 |
| AlmaLinux:10 | fence-agents-cisco-ucs | 4.16.0-21.el10_2.7 | ALSA-2026:94501 |
| AlmaLinux:9 | fence-agents-cisco-ucs | 4.10.0-110.el9_8.8 | ALSA-2026:94500 |
| AlmaLinux:10 | fence-agents-common | 4.16.0-21.el10_2.7 | ALSA-2026:94501 |
| AlmaLinux:9 | fence-agents-common | 4.10.0-110.el9_8.8 | ALSA-2026:94500 |
| AlmaLinux:9 | fence-agents-compute | 4.10.0-110.el9_8.8 | ALSA-2026:94500 |
| AlmaLinux:10 | fence-agents-drac5 | 4.16.0-21.el10_2.7 | ALSA-2026:94501 |
| AlmaLinux:9 | fence-agents-drac5 | 4.10.0-110.el9_8.8 | ALSA-2026:94500 |
| AlmaLinux:10 | fence-agents-eaton-snmp | 4.16.0-21.el10_2.7 | ALSA-2026:94501 |
| AlmaLinux:10 | fence-agents-emerson | 4.16.0-21.el10_2.7 | ALSA-2026:94501 |
| AlmaLinux:10 | fence-agents-eps | 4.16.0-21.el10_2.7 | ALSA-2026:94501 |
| AlmaLinux:10 | fence-agents-gce | 4.16.0-21.el10_2.7 | ALSA-2026:94501 |
| AlmaLinux:9 | fence-agents-gce | 4.10.0-110.el9_8.8 | ALSA-2026:94500 |
| AlmaLinux:10 | fence-agents-heuristics-ping | 4.16.0-21.el10_2.7 | ALSA-2026:94501 |
| AlmaLinux:10 | fence-agents-hpblade | 4.16.0-21.el10_2.7 | ALSA-2026:94501 |
| AlmaLinux:9 | fence-agents-hpblade | 4.10.0-110.el9_8.8 | ALSA-2026:94500 |
| AlmaLinux:10 | fence-agents-ibm-powervs | 4.16.0-21.el10_2.7 | ALSA-2026:94501 |
| AlmaLinux:9 | fence-agents-ibm-powervs | 4.10.0-110.el9_8.8 | ALSA-2026:94500 |
| AlmaLinux:10 | fence-agents-ibm-vpc | 4.16.0-21.el10_2.7 | ALSA-2026:94501 |
| AlmaLinux:9 | fence-agents-ibm-vpc | 4.10.0-110.el9_8.8 | ALSA-2026:94500 |
| AlmaLinux:10 | fence-agents-ibmblade | 4.16.0-21.el10_2.7 | ALSA-2026:94501 |
| AlmaLinux:9 | fence-agents-ibmblade | 4.10.0-110.el9_8.8 | ALSA-2026:94500 |
| AlmaLinux:10 | fence-agents-ifmib | 4.16.0-21.el10_2.7 | ALSA-2026:94501 |
| AlmaLinux:9 | fence-agents-ifmib | 4.10.0-110.el9_8.8 | ALSA-2026:94500 |
| AlmaLinux:10 | fence-agents-ilo-moonshot | 4.16.0-21.el10_2.7 | ALSA-2026:94501 |
| AlmaLinux:9 | fence-agents-ilo-moonshot | 4.10.0-110.el9_8.8 | ALSA-2026:94500 |
| AlmaLinux:10 | fence-agents-ilo-mp | 4.16.0-21.el10_2.7 | ALSA-2026:94501 |
| AlmaLinux:9 | fence-agents-ilo-mp | 4.10.0-110.el9_8.8 | ALSA-2026:94500 |
| AlmaLinux:10 | fence-agents-ilo-ssh | 4.16.0-21.el10_2.7 | ALSA-2026:94501 |
| AlmaLinux:10 | fence-agents-ilo2 | 4.16.0-21.el10_2.7 | ALSA-2026:94501 |
| AlmaLinux:10 | fence-agents-intelmodular | 4.16.0-21.el10_2.7 | ALSA-2026:94501 |
| AlmaLinux:10 | fence-agents-ipdu | 4.16.0-21.el10_2.7 | ALSA-2026:94501 |
| AlmaLinux:10 | fence-agents-ipmilan | 4.16.0-21.el10_2.7 | ALSA-2026:94501 |
| AlmaLinux:10 | fence-agents-kdump | 4.16.0-21.el10_2.7 | ALSA-2026:94501 |
| AlmaLinux:9 | fence-agents-kdump | 4.10.0-110.el9_8.8 | ALSA-2026:94500 |
| AlmaLinux:10 | fence-agents-kubevirt | 4.16.0-21.el10_2.7 | ALSA-2026:94501 |
| AlmaLinux:9 | fence-agents-kubevirt | 4.10.0-110.el9_8.8 | ALSA-2026:94500 |
| AlmaLinux:10 | fence-agents-lpar | 4.16.0-21.el10_2.7 | ALSA-2026:94501 |
| AlmaLinux:9 | fence-agents-lpar | 4.10.0-110.el9_8.8 | ALSA-2026:94500 |
| AlmaLinux:10 | fence-agents-mpath | 4.16.0-21.el10_2.7 | ALSA-2026:94501 |
| AlmaLinux:9 | fence-agents-mpath | 4.10.0-110.el9_8.8 | ALSA-2026:94500 |
| AlmaLinux:10 | fence-agents-nutanix-ahv | 4.16.0-21.el10_2.7 | ALSA-2026:94501 |
| AlmaLinux:9 | fence-agents-nutanix-ahv | 4.10.0-110.el9_8.8 | ALSA-2026:94500 |
| AlmaLinux:10 | fence-agents-openstack | 4.16.0-21.el10_2.7 | ALSA-2026:94501 |
| AlmaLinux:9 | fence-agents-openstack | 4.10.0-110.el9_8.8 | ALSA-2026:94500 |
| AlmaLinux:10 | fence-agents-redfish | 4.16.0-21.el10_2.7 | ALSA-2026:94501 |
| AlmaLinux:9 | fence-agents-redfish | 4.10.0-110.el9_8.8 | ALSA-2026:94500 |
| AlmaLinux:10 | fence-agents-rhevm | 4.16.0-21.el10_2.7 | ALSA-2026:94501 |
| AlmaLinux:9 | fence-agents-rhevm | 4.10.0-110.el9_8.8 | ALSA-2026:94500 |
| AlmaLinux:10 | fence-agents-rsa | 4.16.0-21.el10_2.7 | ALSA-2026:94501 |
| AlmaLinux:9 | fence-agents-rsa | 4.10.0-110.el9_8.8 | ALSA-2026:94500 |
| AlmaLinux:10 | fence-agents-rsb | 4.16.0-21.el10_2.7 | ALSA-2026:94501 |
| AlmaLinux:10 | fence-agents-sbd | 4.16.0-21.el10_2.7 | ALSA-2026:94501 |
| AlmaLinux:10 | fence-agents-scsi | 4.16.0-21.el10_2.7 | ALSA-2026:94501 |
| AlmaLinux:9 | fence-agents-scsi | 4.10.0-110.el9_8.8 | ALSA-2026:94500 |
| AlmaLinux:10 | fence-agents-virsh | 4.16.0-21.el10_2.7 | ALSA-2026:94501 |
| AlmaLinux:9 | fence-agents-virsh | 4.10.0-110.el9_8.8 | ALSA-2026:94500 |
| AlmaLinux:10 | fence-agents-vmware-rest | 4.16.0-21.el10_2.7 | ALSA-2026:94501 |
| AlmaLinux:9 | fence-agents-vmware-rest | 4.10.0-110.el9_8.8 | ALSA-2026:94500 |
| AlmaLinux:10 | fence-agents-vmware-soap | 4.16.0-21.el10_2.7 | ALSA-2026:94501 |
| AlmaLinux:10 | fence-agents-wti | 4.16.0-21.el10_2.7 | ALSA-2026:94501 |
| AlmaLinux:10 | fence-agents-zvm | 4.16.0-21.el10_2.7 | ALSA-2026:94501 |
| AlmaLinux:10 | fence-virt | 4.16.0-21.el10_2.7 | ALSA-2026:94501 |
| AlmaLinux:9 | fence-virt | 4.10.0-110.el9_8.8 | ALSA-2026:94500 |
| AlmaLinux:10 | fence-virtd | 4.16.0-21.el10_2.7 | ALSA-2026:94501 |
| AlmaLinux:10 | fence-virtd-cpg | 4.16.0-21.el10_2.7 | ALSA-2026:94501 |
| AlmaLinux:10 | fence-virtd-libvirt | 4.16.0-21.el10_2.7 | ALSA-2026:94501 |
| AlmaLinux:9 | fence-virtd-libvirt | 4.10.0-110.el9_8.8 | ALSA-2026:94500 |
| AlmaLinux:10 | fence-virtd-multicast | 4.16.0-21.el10_2.7 | ALSA-2026:94501 |
| AlmaLinux:9 | fence-virtd-multicast | 4.10.0-110.el9_8.8 | ALSA-2026:94500 |
| AlmaLinux:10 | fence-virtd-serial | 4.16.0-21.el10_2.7 | ALSA-2026:94501 |
| AlmaLinux:9 | fence-virtd-serial | 4.10.0-110.el9_8.8 | ALSA-2026:94500 |
| AlmaLinux:10 | fence-virtd-tcp | 4.16.0-21.el10_2.7 | ALSA-2026:94501 |
| AlmaLinux:10 | ha-cloud-support | 4.16.0-21.el10_2.7 | ALSA-2026:94501 |
| AlmaLinux:9 | ha-cloud-support | 4.10.0-110.el9_8.8 | ALSA-2026:94500 |
| Debian:12 | pyjwt | no fix listed | DEBIAN-CVE-2026-102268 |
| Debian:13 | pyjwt | no fix listed | DEBIAN-CVE-2026-102268 |
| Debian:14 | pyjwt | 2.14.0-1 | DEBIAN-CVE-2026-102268 |
| PyPI | pyjwt | 2.14.0 | GHSA-ffc3-869f-jxw9 |
| PyPI | pyjwt | 2.14.0 | PYSEC-2026-4145 |
| Rocky Linux:10 | fence-agents | 0:4.16.0-21.el10_2.7 | RLSA-2026:94501 |
| Rocky Linux:9 | fence-agents | 0:4.10.0-110.el9_8.8 | RLSA-2026:94500 |
| Ubuntu:22.04:LTS | pyjwt | 2.3.0-1ubuntu0.5 | UBUNTU-CVE-2026-102268 |
| Ubuntu:22.04:LTS | pyjwt | 2.3.0-1ubuntu0.5 | USN-8916-1 |
| Ubuntu:24.04:LTS | pyjwt | 2.7.0-1ubuntu0.3 | USN-8916-1 |
| Ubuntu:24.04:LTS | pyjwt | 2.7.0-1ubuntu0.3 | UBUNTU-CVE-2026-102268 |
| Ubuntu:26.04:LTS | pyjwt | 2.10.1-4ubuntu1.2 | USN-8916-1 |
| Ubuntu:26.04:LTS | pyjwt | 2.10.1-4ubuntu1.2 | UBUNTU-CVE-2026-102268 |
| Ubuntu:26.10 | pyjwt | 2.13.0-1ubuntu1 | UBUNTU-CVE-2026-102268 |
| Ubuntu:26.10 | pyjwt | 2.13.0-1ubuntu1 | USN-8916-2 |
Affected products (as reported)
Weakness: CWE-347 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
References
- https://github.com/jpadilla/pyjwt/security/advisories/GHSA-ffc3-869f-jxw9 x_refsource_CONFIRM
- https://github.com/jpadilla/pyjwt/commit/8b4e233a22206b34ec1186e912e75c0b2396ac07 x_refsource_MISC
- https://github.com/jpadilla/pyjwt/releases/tag/2.14.0 x_refsource_MISC