CVE-2026-55556

Exploitation

Public exploit code exists. CISA's assessment records a public proof of concept. That is not a report of exploitation in the wild.

SSVC decision

• ExploitationpocPublic proof-of-concept exploit code exists. Not a report of exploitation in the wild.
• AutomatableyesAn attacker can reliably automate reconnaissance through exploitation, so this scales.
• Technical ImpactpartialSuccessful exploitation gives limited control of the vulnerable component.

CISA publishes the decision points, not a final SSVC decision. The decision also depends on mission and well-being impact, which is a property of your deployment rather than of the vulnerability.

EPSS probability

0.85% probability of exploitation activity in the next 30 days.

EPSS percentile

Equal to or higher than the score of 58.1% of scored records. A rank, not a probability.

NVD base score

8.2 (CVSS v4.0), scored by the NVD independently of the CNA.

NVD CVSS vector

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

NVD analysis status

Awaiting Analysis. NVD last modified this record on 2026-09-24.

Red Hat severity

Important. Red Hat's rating for its own products, not a CVSS rating.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

Published

2026-09-18 16:53Z1 MO AGO

Last updated

2026-09-22 15:04Z1 MO AGO

Reserved

2026-06-16

Assigning CNA

GitHub_M

Record state

PUBLISHED

Severity

High (CVSS 8.2)

CNA CVSS vector

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

Weaknesses

• CWE-122Heap-based Buffer OverflowVariant
• CWE-131Incorrect Calculation of Buffer SizeBase

Data version

5.2

Document digest

6e3fd3ce84195c63869681b6a45c4c7a1aa82ca7c7a71e001346b9b8b7261d0d

• github.comhttps://github.com/rsyslog/rsyslog/security/advisories/GHSA-947w-69ph-mc2rx_refsource_CONFIRM
• github.comhttps://github.com/rsyslog/rsyslog/pull/6722x_refsource_MISC
• github.comhttps://github.com/rsyslog/rsyslog/commit/acde2ba25ea33816694b787859f4a727a247b6d6x_refsource_MISC
• github.comhttps://github.com/rsyslog/rsyslog/releases/tag/v8.2604.0x_refsource_MISC
• www.openwall.comhttp://www.openwall.com/lists/oss-security/2026/06/23/4