Vulnerability · Published Aug 27, 2026 · Assigned by redhat

CVE-2026-78002Rsyslog: rsyslog: denial of service via heap buffer overflow in rainerscript replace() function

High 7.5

In plain English

A high-severity security flaw in Red Hat Enterprise Linux 10 from Red Hat. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 1.1% (higher than 65% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)7.5High

Exploit odds (30 days)1.1%top 35.2% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

A flaw was found in rsyslog. An unauthenticated remote attacker can trigger a heap buffer overflow in the RainerScript `replace()` function by sending specially crafted syslog messages. This vulnerability arises from an incorrect buffer size calculation during string replacement, causing memory corruption. Successful exploitation can lead to a denial of service (DoS) for the affected system.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
AlmaLinux:10	rsyslog	8.2510.0-5.el10_2.2	ALSA-2026:69541
AlmaLinux:8	rsyslog	8.2102.0-15.el8_10.3	ALSA-2026:80817
AlmaLinux:9	rsyslog	8.2510.0-2.el9_8.2	ALSA-2026:69540
AlmaLinux:10	rsyslog-crypto	8.2510.0-5.el10_2.2	ALSA-2026:69541
AlmaLinux:8	rsyslog-crypto	8.2102.0-15.el8_10.3	ALSA-2026:80817
AlmaLinux:9	rsyslog-crypto	8.2510.0-2.el9_8.2	ALSA-2026:69540
AlmaLinux:10	rsyslog-doc	8.2510.0-5.el10_2.2	ALSA-2026:69541
AlmaLinux:8	rsyslog-doc	8.2102.0-15.el8_10.3	ALSA-2026:80817
AlmaLinux:9	rsyslog-doc	8.2510.0-2.el9_8.2	ALSA-2026:69540
AlmaLinux:10	rsyslog-elasticsearch	8.2510.0-5.el10_2.2	ALSA-2026:69541
AlmaLinux:8	rsyslog-elasticsearch	8.2102.0-15.el8_10.3	ALSA-2026:80817
AlmaLinux:9	rsyslog-elasticsearch	8.2510.0-2.el9_8.2	ALSA-2026:69540
AlmaLinux:10	rsyslog-gnutls	8.2510.0-5.el10_2.2	ALSA-2026:69541
AlmaLinux:8	rsyslog-gnutls	8.2102.0-15.el8_10.3	ALSA-2026:80817
AlmaLinux:9	rsyslog-gnutls	8.2510.0-2.el9_8.2	ALSA-2026:69540
AlmaLinux:10	rsyslog-gssapi	8.2510.0-5.el10_2.2	ALSA-2026:69541
AlmaLinux:8	rsyslog-gssapi	8.2102.0-15.el8_10.3	ALSA-2026:80817
AlmaLinux:9	rsyslog-gssapi	8.2510.0-2.el9_8.2	ALSA-2026:69540
AlmaLinux:10	rsyslog-kafka	8.2510.0-5.el10_2.2	ALSA-2026:69541
AlmaLinux:8	rsyslog-kafka	8.2102.0-15.el8_10.3	ALSA-2026:80817
AlmaLinux:9	rsyslog-kafka	8.2510.0-2.el9_8.2	ALSA-2026:69540
AlmaLinux:9	rsyslog-logrotate	8.2510.0-2.el9_8.2	ALSA-2026:69540
AlmaLinux:10	rsyslog-mmaudit	8.2510.0-5.el10_2.2	ALSA-2026:69541
AlmaLinux:8	rsyslog-mmaudit	8.2102.0-15.el8_10.3	ALSA-2026:80817
AlmaLinux:9	rsyslog-mmaudit	8.2510.0-2.el9_8.2	ALSA-2026:69540
AlmaLinux:10	rsyslog-mmfields	8.2510.0-5.el10_2.2	ALSA-2026:69541
AlmaLinux:8	rsyslog-mmfields	8.2102.0-15.el8_10.3	ALSA-2026:80817
AlmaLinux:9	rsyslog-mmfields	8.2510.0-2.el9_8.2	ALSA-2026:69540
AlmaLinux:10	rsyslog-mmjsonparse	8.2510.0-5.el10_2.2	ALSA-2026:69541
AlmaLinux:8	rsyslog-mmjsonparse	8.2102.0-15.el8_10.3	ALSA-2026:80817
AlmaLinux:9	rsyslog-mmjsonparse	8.2510.0-2.el9_8.2	ALSA-2026:69540
AlmaLinux:10	rsyslog-mmkubernetes	8.2510.0-5.el10_2.2	ALSA-2026:69541
AlmaLinux:8	rsyslog-mmkubernetes	8.2102.0-15.el8_10.3	ALSA-2026:80817
AlmaLinux:9	rsyslog-mmkubernetes	8.2510.0-2.el9_8.2	ALSA-2026:69540
AlmaLinux:10	rsyslog-mmnormalize	8.2510.0-5.el10_2.2	ALSA-2026:69541
AlmaLinux:8	rsyslog-mmnormalize	8.2102.0-15.el8_10.3	ALSA-2026:80817
AlmaLinux:9	rsyslog-mmnormalize	8.2510.0-2.el9_8.2	ALSA-2026:69540
AlmaLinux:10	rsyslog-mmsnmptrapd	8.2510.0-5.el10_2.2	ALSA-2026:69541
AlmaLinux:8	rsyslog-mmsnmptrapd	8.2102.0-15.el8_10.3	ALSA-2026:80817
AlmaLinux:9	rsyslog-mmsnmptrapd	8.2510.0-2.el9_8.2	ALSA-2026:69540
AlmaLinux:10	rsyslog-mysql	8.2510.0-5.el10_2.2	ALSA-2026:69541
AlmaLinux:8	rsyslog-mysql	8.2102.0-15.el8_10.3	ALSA-2026:80817
AlmaLinux:9	rsyslog-mysql	8.2510.0-2.el9_8.2	ALSA-2026:69540
AlmaLinux:10	rsyslog-omamqp1	8.2510.0-5.el10_2.2	ALSA-2026:69541
AlmaLinux:8	rsyslog-omamqp1	8.2102.0-15.el8_10.3	ALSA-2026:80817
AlmaLinux:9	rsyslog-omamqp1	8.2510.0-2.el9_8.2	ALSA-2026:69540
AlmaLinux:10	rsyslog-openssl	8.2510.0-5.el10_2.2	ALSA-2026:69541
AlmaLinux:8	rsyslog-openssl	8.2102.0-15.el8_10.3	ALSA-2026:80817
AlmaLinux:9	rsyslog-openssl	8.2510.0-2.el9_8.2	ALSA-2026:69540
AlmaLinux:10	rsyslog-pgsql	8.2510.0-5.el10_2.2	ALSA-2026:69541
AlmaLinux:8	rsyslog-pgsql	8.2102.0-15.el8_10.3	ALSA-2026:80817
AlmaLinux:9	rsyslog-pgsql	8.2510.0-2.el9_8.2	ALSA-2026:69540
AlmaLinux:10	rsyslog-relp	8.2510.0-5.el10_2.2	ALSA-2026:69541
AlmaLinux:8	rsyslog-relp	8.2102.0-15.el8_10.3	ALSA-2026:80817
AlmaLinux:9	rsyslog-relp	8.2510.0-2.el9_8.2	ALSA-2026:69540
AlmaLinux:10	rsyslog-snmp	8.2510.0-5.el10_2.2	ALSA-2026:69541
AlmaLinux:8	rsyslog-snmp	8.2102.0-15.el8_10.3	ALSA-2026:80817
AlmaLinux:9	rsyslog-snmp	8.2510.0-2.el9_8.2	ALSA-2026:69540
AlmaLinux:10	rsyslog-udpspoof	8.2510.0-5.el10_2.2	ALSA-2026:69541
AlmaLinux:8	rsyslog-udpspoof	8.2102.0-15.el8_10.3	ALSA-2026:80817
AlmaLinux:9	rsyslog-udpspoof	8.2510.0-2.el9_8.2	ALSA-2026:69540
Alpine:v3.24	rsyslog	8.2608.0-r0	ALPINE-CVE-2026-78002
Debian:12	rsyslog	no fix listed	DEBIAN-CVE-2026-78002
Debian:13	rsyslog	8.2504.0-1+deb13u2	DEBIAN-CVE-2026-78002
Debian:14	rsyslog	8.2608.0-4	DEBIAN-CVE-2026-78002
Rocky Linux:10	rsyslog	0:8.2510.0-5.el10_2.2	RLSA-2026:69541
Rocky Linux:8	rsyslog	0:8.2102.0-15.el8_10.3	RLSA-2026:80817
Rocky Linux:9	rsyslog	0:8.2510.0-2.el9_8.2	RLSA-2026:69540
Ubuntu:22.04:LTS	rsyslog	8.2112.0-2ubuntu2.5	UBUNTU-CVE-2026-78002
Ubuntu:22.04:LTS	rsyslog	8.2112.0-2ubuntu2.5	USN-8786-1
Ubuntu:24.04:LTS	rsyslog	8.2312.0-3ubuntu9.4	UBUNTU-CVE-2026-78002
Ubuntu:24.04:LTS	rsyslog	8.2312.0-3ubuntu9.4	USN-8786-1
Ubuntu:26.04:LTS	rsyslog	8.2512.0-1ubuntu4.2	USN-8786-1
Ubuntu:26.04:LTS	rsyslog	8.2512.0-1ubuntu4.2	UBUNTU-CVE-2026-78002

Affected products (as reported)

Vendor	Product	Versions
Red Hat	Red Hat Enterprise Linux 10	see references
Red Hat	Red Hat Enterprise Linux 10.0 Extended Update Support	see references
Red Hat	Red Hat Enterprise Linux 8	see references
Red Hat	Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support	see references
Red Hat	Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On	see references
Red Hat	Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support	see references
Red Hat	Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On	see references
Red Hat	Red Hat Enterprise Linux 8.8 Telecommunications Update Service	see references
Red Hat	Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions	see references
Red Hat	Red Hat Enterprise Linux 9	see references
Red Hat	Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions	see references
Red Hat	Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions	see references
Red Hat	Red Hat Enterprise Linux 9.6 Extended Update Support	see references
Red Hat	Red Hat Update Infrastructure 5	see references
Red Hat	Red Hat Enterprise Linux 6	see references
Red Hat	Red Hat Enterprise Linux 6	see references
Red Hat	Red Hat Enterprise Linux 7	see references

Weakness: CWE-131 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References

RHSA-2026:69540 vendor-advisory, x_refsource_REDHAT
RHSA-2026:69541 vendor-advisory, x_refsource_REDHAT
RHSA-2026:71603 vendor-advisory, x_refsource_REDHAT
RHSA-2026:80817 vendor-advisory, x_refsource_REDHAT
RHSA-2026:81321 vendor-advisory, x_refsource_REDHAT
RHSA-2026:84576 vendor-advisory, x_refsource_REDHAT
RHSA-2026:86124 vendor-advisory, x_refsource_REDHAT
RHSA-2026:87408 vendor-advisory, x_refsource_REDHAT
RHSA-2026:90349 vendor-advisory, x_refsource_REDHAT
RHSA-2026:91582 vendor-advisory, x_refsource_REDHAT
RHSA-2026:95573 vendor-advisory, x_refsource_REDHAT
https://access.redhat.com/security/cve/CVE-2026-78002 vdb-entry, x_refsource_REDHAT
RHBZ#2521135 issue-tracking, x_refsource_REDHAT
https://github.com/rsyslog/rsyslog/security/advisories/GHSA-g72f-gc6v-f2w3
http://www.openwall.com/lists/oss-security/2026/08/29/1