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7.5
HIGH CVSS 3.1
CVE-2026-78002
Rsyslog: rsyslog: denial of service via heap buffer overflow in rainerscript replace() function
Overview
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.

Details
INFO

Published Date :

Aug. 27, 2026, 5:20 p.m.

Last Modified :

Sept. 25, 2026, 3:17 p.m.

Remotely Exploit :

Yes !

Source :

[email protected]
Impact
Affected Products

The following products are affected by CVE-2026-78002 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Redhat enterprise_linux
2 Redhat update_infrastructure
3 Redhat enterprise_linux
1 Ubuntu libefiboot
: Total Affected Vendor : 2 | Products : 4
Scoring
CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 134c704f-9b21-4f2e-91b3-4a467353bcc0
CVSS 3.1 HIGH 53f830b8-0a3f-465b-8143-3b8a9948e749
CVSS 3.1 HIGH [email protected]
CVSS 3.1 HIGH MITRE-CVE
Solution
Update rsyslog to the latest version to fix a heap buffer overflow vulnerability.
  • Update rsyslog to the latest version.
  • Apply vendor patches for rsyslog.
  • Validate RainerScript replace() function usage.
References
References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2026-78002.

URL Resource
https://access.redhat.com/errata/RHSA-2026:69540
https://access.redhat.com/errata/RHSA-2026:69541
https://access.redhat.com/errata/RHSA-2026:71603
https://access.redhat.com/security/cve/CVE-2026-78002
https://bugzilla.redhat.com/show_bug.cgi?id=2521135
https://github.com/rsyslog/rsyslog/security/advisories/GHSA-g72f-gc6v-f2w3
http://www.openwall.com/lists/oss-security/2026/08/29/1
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-78002 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-78002 weaknesses.

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2026-78002 vulnerability anywhere in the article.

Results are limited to the first 20 news articles due to potential performance issues.

The following table lists the changes that have been made to the CVE-2026-78002 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • CVE Modified by [email protected]

    Sep. 25, 2026

    Action Type Old Value New Value
    Added Affected Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/78xxx/CVE-2026-78002.json">CVE-2026-78002</a>
  • CVE Modified by [email protected]

    Sep. 24, 2026

    Action Type Old Value New Value
    Added Affected Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/78xxx/CVE-2026-78002.json">CVE-2026-78002</a>
  • CVE Modified by [email protected]

    Sep. 24, 2026

    Action Type Old Value New Value
    Added Affected Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/78xxx/CVE-2026-78002.json">CVE-2026-78002</a>
    Added Reference https://access.redhat.com/errata/RHSA-2026:71603
  • CVE Modified by [email protected]

    Sep. 22, 2026

    Action Type Old Value New Value
    Added Affected Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/78xxx/CVE-2026-78002.json">CVE-2026-78002</a>
    Added Reference https://access.redhat.com/errata/RHSA-2026:69540
  • CVE Modified by [email protected]

    Sep. 21, 2026

    Action Type Old Value New Value
    Added Affected Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/78xxx/CVE-2026-78002.json">CVE-2026-78002</a>
    Added Reference https://access.redhat.com/errata/RHSA-2026:69541
  • CVE Modified by [email protected]

    Sep. 21, 2026

    Action Type Old Value New Value
    Added Affected Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/78xxx/CVE-2026-78002.json">CVE-2026-78002</a>
  • CVE Modified by [email protected]

    Sep. 04, 2026

    Action Type Old Value New Value
    Added Affected Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/78xxx/CVE-2026-78002.json">CVE-2026-78002</a>
  • CVE Modified by af854a3a-2127-422b-91ae-364da2661108

    Aug. 29, 2026

    Action Type Old Value New Value
    Added Reference http://www.openwall.com/lists/oss-security/2026/08/29/1
  • CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0

    Aug. 27, 2026

    Action Type Old Value New Value
    Added SSVC {'id': 'CVE-2026-78002', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'yes'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-08-27T18:29:21.461066Z'}
  • CVE Modified by [email protected]

    Aug. 27, 2026

    Action Type Old Value New Value
    Added Affected Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/78xxx/CVE-2026-78002.json">CVE-2026-78002</a>
  • New CVE Received by [email protected]

    Aug. 27, 2026

    Action Type Old Value New Value
    Added 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.
    Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
    Added CWE CWE-131
    Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/78xxx/CVE-2026-78002.json">CVE-2026-78002</a>
    Added Reference https://access.redhat.com/security/cve/CVE-2026-78002
    Added Reference https://bugzilla.redhat.com/show_bug.cgi?id=2521135
    Added Reference https://github.com/rsyslog/rsyslog/security/advisories/GHSA-g72f-gc6v-f2w3
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.
CVSS
Vulnerability Scoring Details
Base CVSS Score: 7.5
Attack Vector
Attack Complexity
Privileges Required
User Interaction
Scope
Confidentiality Impact
Integrity Impact
Availability Impact