A flaw was found in rsyslog. An unauthenticated remote attacker can trigger a heap buffer overflow in the RainerScript replace() function by sending… (CVE-2026-78002)
A heap buffer overflow vulnerability exists in the RainerScript replace() function of rsyslog. An unauthenticated remote attacker can trigger this by sending specially crafted syslog messages. The flaw is due to incorrect buffer size calculation during string replacement, leading to memory corruption. Exploitation can cause a denial of service (DoS) on the affected system. The vulnerability affects multiple specific Ubuntu package versions of rsyslog. The CVSS score is 7.5, indicating a medium severity level.
AI Analysis
Technical Summary
CVE-2026-78002 is a heap buffer overflow vulnerability in rsyslog's RainerScript replace() function. It arises from incorrect buffer size calculation during string replacement when processing specially crafted syslog messages. An unauthenticated remote attacker can exploit this flaw to cause memory corruption, resulting in denial of service (DoS). The vulnerability affects numerous specific Ubuntu rsyslog package versions. There are no known exploits in the wild, and no patch information is provided in the input data.
Potential Impact
Successful exploitation leads to denial of service (DoS) by causing memory corruption through a heap buffer overflow. There is no indication of confidentiality or integrity impact. The vulnerability can be triggered remotely without authentication.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a patch is available, consider restricting access to syslog services from untrusted sources to reduce exposure.
A flaw was found in rsyslog. An unauthenticated remote attacker can trigger a heap buffer overflow in the RainerScript replace() function by sending… (CVE-2026-78002)
Description
A heap buffer overflow vulnerability exists in the RainerScript replace() function of rsyslog. An unauthenticated remote attacker can trigger this by sending specially crafted syslog messages. The flaw is due to incorrect buffer size calculation during string replacement, leading to memory corruption. Exploitation can cause a denial of service (DoS) on the affected system. The vulnerability affects multiple specific Ubuntu package versions of rsyslog. The CVSS score is 7.5, indicating a medium severity level.
CVSS v3.1
Score 7.5high
Affected software
pkg:deb/ubuntu/rsyslog?arch=source&distro=trustypkg:deb/ubuntu/rsyslog?arch=source&distro=esm-infra/xenialpkg:deb/ubuntu/rsyslog?arch=source&distro=bionicpkg:deb/ubuntu/rsyslog?arch=source&distro=focalpkg:deb/ubuntu/rsyslog?arch=source&distro=jammypkg:deb/ubuntu/rsyslog?arch=source&distro=noblepkg:deb/ubuntu/rsyslog?arch=source&distro=resoluteRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-78002 is a heap buffer overflow vulnerability in rsyslog's RainerScript replace() function. It arises from incorrect buffer size calculation during string replacement when processing specially crafted syslog messages. An unauthenticated remote attacker can exploit this flaw to cause memory corruption, resulting in denial of service (DoS). The vulnerability affects numerous specific Ubuntu rsyslog package versions. There are no known exploits in the wild, and no patch information is provided in the input data.
Potential Impact
Successful exploitation leads to denial of service (DoS) by causing memory corruption through a heap buffer overflow. There is no indication of confidentiality or integrity impact. The vulnerability can be triggered remotely without authentication.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a patch is available, consider restricting access to syslog services from untrusted sources to reduce exposure.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- UBUNTU-CVE-2026-78002
- Osv Schema Version
- 1.7.0
- Ecosystems
- ["Ubuntu:14.04:LTS","Ubuntu:Pro:16.04:LTS","Ubuntu:18.04:LTS","Ubuntu:20.04:LTS","Ubuntu:22.04:LTS","Ubuntu:24.04:LTS","Ubuntu:26.04:LTS"]
- Cvss Version
- 3.1
- State
- PUBLISHED
Threat ID: 6aa47ec055bf5e2cf58579f8
Added to database: 09/11/2026, 22:20:48 UTC
Last enriched: 09/11/2026, 22:34:07 UTC
Last updated: 09/12/2026, 03:02:27 UTC
Views: 5
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