Rsyslog is a rocket-fast system for log processing. Modules for TCP syslog reception have a potential heap buffer overflow when octet-counted framing is used. This can result in a segfault or some other malfunction. As of our understanding, this vulnerability can not be used for remote code execution. But there may still be a slight chance for experts to do that. The bug occurs when the octet count is read. While there is a check for the maximum number of octets, digits are written to a heap buffer even when the octet count is over the maximum, This can be used to overrun the memory buffer. However, once the sequence of digits stop, no additional characters can be added to the buffer. In our opinion, this makes remote exploits impossible or at least highly complex. Octet-counted framing is one of two potential framing modes. It is relatively uncommon, but enabled by default on receivers. Modules `imtcp`, `imptcp`, `imgssapi`, and `imhttp` are used for regular syslog message reception. It is best practice not to directly expose them to the public. When this practice is followed, the risk is considerably lower. Module `imdiag` is a diagnostics module primarily intended for testbench runs. We do not expect it to be present on any production installation. Octet-counted framing is not very common. Usually, it needs to be specifically enabled at senders. If users do not need it, they can turn it off for the most important modules. This will mitigate the vulnerability.
Advisories
Source ID Title
Debian DLA Debian DLA DLA-3016-1 rsyslog security update
Debian DSA Debian DSA DSA-5150-1 rsyslog security update
EUVD EUVD EUVD-2022-29662 Rsyslog is a rocket-fast system for log processing. Modules for TCP syslog reception have a potential heap buffer overflow when octet-counted framing is used. This can result in a segfault or some other malfunction. As of our understanding, this vulnerability can not be used for remote code execution. But there may still be a slight chance for experts to do that. The bug occurs when the octet count is read. While there is a check for the maximum number of octets, digits are written to a heap buffer even when the octet count is over the maximum, This can be used to overrun the memory buffer. However, once the sequence of digits stop, no additional characters can be added to the buffer. In our opinion, this makes remote exploits impossible or at least highly complex. Octet-counted framing is one of two potential framing modes. It is relatively uncommon, but enabled by default on receivers. Modules `imtcp`, `imptcp`, `imgssapi`, and `imhttp` are used for regular syslog message reception. It is best practice not to directly expose them to the public. When this practice is followed, the risk is considerably lower. Module `imdiag` is a diagnostics module primarily intended for testbench runs. We do not expect it to be present on any production installation. Octet-counted framing is not very common. Usually, it needs to be specifically enabled at senders. If users do not need it, they can turn it off for the most important modules. This will mitigate the vulnerability.
Ubuntu USN Ubuntu USN USN-5404-1 Rsyslog vulnerability
Ubuntu USN Ubuntu USN USN-5404-2 Rsyslog vulnerability
Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

Wed, 23 Apr 2025 19:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2025-04-23T18:31:22.233Z

Reserved: 2022-02-10T00:00:00.000Z

Link: CVE-2022-24903

cve-icon Vulnrichment

Updated: 2024-08-03T04:29:01.617Z

cve-icon NVD

Status : Modified

Published: 2022-05-06T00:15:07.873

Modified: 2024-11-21T06:51:21.620

Link: CVE-2022-24903

cve-icon Redhat

Severity : Important

Publid Date: 2022-05-05T00:00:00Z

Links: CVE-2022-24903 - Bugzilla

cve-icon OpenCVE Enrichment

No data.