Description
An issue was discovered in Rsyslog v8.1908.0. contrib/pmcisconames/pmcisconames.c has a heap overflow in the parser for Cisco log messages. The parser tries to locate a log message delimiter (in this case, a space or a colon), but fails to account for strings that do not satisfy this constraint. If the string does not match, then the variable lenMsg will reach the value zero and will skip the sanity check that detects invalid log messages. The message will then be considered valid, and the parser will eat up the nonexistent colon delimiter. In doing so, it will decrement lenMsg, a signed integer, whose value was zero and now becomes minus one. The following step in the parser is to shift left the contents of the message. To do this, it will call memmove with the right pointers to the target and destination strings, but the lenMsg will now be interpreted as a huge value, causing a heap overflow.
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | rsyslog | 8.1910.0-1 | — |
| Debian 13 | rsyslog | 8.1910.0-1 | — |
| Debian 12 | rsyslog | 8.1910.0-1 | — |
| Debian 9 | rsyslog | 8.24.0-1+deb9u1 | DLA-2835-1 |
| Debian 8 | rsyslog | 8.4.2-1+deb8u3 | DLA-1952-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 14.04 LTS | rsyslog | No fix yet | — |
Show 2 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 18.04 LTS | rsyslog | No fix yet | — |
| Ubuntu Pro 16.04 LTS | rsyslog | 8.16.0-1ubuntu3.1+esm1 | USN-5419-1 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 8 | rsyslog +15 | 8.1911.0-3.el8 | RHSA-2020:1702 |
| RHEL 7 | rsyslog +17 | 8.24.0-52.el7 | RHSA-2020:1000 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP1 | rsyslog | 8.33.1-3.22.4 | SUSE-SU-2019:2937-1 |
| SLES 15 | rsyslog | 8.33.1-3.22.4 | SUSE-SU-2019:2937-1 |
| SLES 12 SP5 | rsyslog | 8.24.0-3.33.2 | SUSE-RU-2019:2816-1 |
| SLES 12 SP4 | rsyslog | 8.24.0-3.33.2 | SUSE-RU-2019:2816-1 |
| SLES 12 SP2 | rsyslog | 8.4.0-18.13.1 | SUSE-SU-2020:0512-1 |
Show 6 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 12 SP1 | rsyslog | 8.4.0-13.8.1 | SUSE-SU-2020:0424-1 |
| SLES for SAP 12 SP5 | rsyslog | 8.24.0-3.33.2 | SUSE-RU-2019:2816-1 |
| SLES for SAP 12 SP4 | rsyslog | 8.24.0-3.33.2 | SUSE-RU-2019:2816-1 |
| SLES for SAP 12 SP2 | rsyslog | 8.4.0-18.13.1 | SUSE-SU-2020:0512-1 |
| SLES for SAP 12 SP1 | rsyslog | 8.4.0-13.8.1 | SUSE-SU-2020:0424-1 |
| SUSE OpenStack Cloud 7 | rsyslog | 8.4.0-18.13.1 | SUSE-SU-2020:0512-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Leap 15.1 | rsyslog | 8.33.1-lp151.6.10.1 | openSUSE-SU-2019:2501-1 |
| openSUSE Leap 15.0 | rsyslog | 8.33.1-lp150.2.19.1 | openSUSE-SU-2019:2500-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | rsyslog | 8.1908.0-r1 | — |
| Alpine v3.23 | rsyslog | 8.1908.0-r1 | — |
| Alpine v3.22 | rsyslog | 8.1908.0-r1 | — |
| Alpine v3.21 | rsyslog | 8.1908.0-r1 | — |
| Alpine v3.20 | rsyslog | 8.1908.0-r1 | — |
Show 13 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.19 | rsyslog | 8.1908.0-r1 | — |
| Alpine v3.18 | rsyslog | 8.1908.0-r1 | — |
| Alpine v3.17 | rsyslog | 8.1908.0-r1 | — |
| Alpine v3.16 | rsyslog | 8.1908.0-r1 | — |
| Alpine v3.15 | rsyslog | 8.1908.0-r1 | — |
| Alpine v3.14 | rsyslog | 8.1908.0-r1 | — |
| Alpine v3.13 | rsyslog | 8.1908.0-r1 | — |
| Alpine v3.12 | rsyslog | 8.1908.0-r1 | — |
| Alpine v3.11 | rsyslog | 8.1908.0-r1 | — |
| Alpine v3.10 | rsyslog | 8.1904.0-r1 | — |
| Alpine v3.9 | rsyslog | 8.40.0-r4 | — |
| Alpine v3.8 | rsyslog | 8.34.0-r1 | — |
| Alpine v3.7 | rsyslog | 8.31.0-r1 | — |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2 | rsyslog +17 | 8.24.0-52.amzn2 | ALAS2-2020-1447 |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 8 | rsyslog +15 | 8.1911.0-3.el8 | ELSA-2020-1702 |
| Oracle Linux 7 | rsyslog +17 | 8.24.0-52.el7 | ELSA-2020-1000 |
Advisories 14
- RHSA-2020:1000 Red Hat Security Advisory: rsyslog security, bug fix, and enhancement update Red Hat Security Advisories (RHSA) · Jun 26, 2026
- USN-5419-1 rsyslog vulnerabilities Ubuntu Security Notices (USN) · Jun 25, 2026
- DLA-1952-1 rsyslog - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DLA-2835-1 rsyslog - security update Debian Security (DSA / DLA) · Mar 9, 2026
- SUSE-SU-2020:0512-1 Security update for rsyslog SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2019:2501-1 Security update for rsyslog SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2019:2937-1 Security update for rsyslog SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2020:0424-1 Security update for rsyslog SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2019:2500-1 Security update for rsyslog SUSE / openSUSE Security Updates · Feb 4, 2026
- RHSA-2020:1702 Red Hat Security Advisory: rsyslog security, bug fix, and enhancement update Red Hat Security Advisories (RHSA) · Nov 22, 2025
- SUSE-RU-2019:2816-1 Recommended update for rsyslog SUSE / openSUSE Security Updates · May 2, 2025
- ALAS2-2020-1447 Moderate: rsyslog security update (Amazon Linux 2) Amazon Linux Security Center (ALAS) · Jul 1, 2020
- ELSA-2020-1702 Moderate: rsyslog security, bug fix, and enhancement update (Oracle Linux 8) Oracle Linux Security Advisories (ELSA) · May 5, 2020
- ELSA-2020-1000 Moderate: rsyslog security, bug fix, and enhancement update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Apr 6, 2020
References
- https://github.com/rsyslog/rsyslog/blob/v8-stable/ChangeLog
- https://github.com/rsyslog/rsyslog/pull/3883
- openSUSE-SU-2019:2500 vendor-advisory
- openSUSE-SU-2019:2501 vendor-advisory
- FEDORA-2019-ea7d5876a4 vendor-advisory
- FEDORA-2019-1fb95ae48d vendor-advisory
- [debian-lts-announce] 20211130 [SECURITY] [DLA 2835-1] rsyslog security update mailing-list