rsyslog imhttp Basic Auth heap-based overflow

CVSS Meta Temp Score
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CTI Interest Score
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6.0$0-$5k1.33

Summaryinfo

A vulnerability, which was classified as critical, was found in rsyslog. Affected by this issue is some unknown functionality of the component imhttp Basic Auth. Executing a manipulation can lead to heap-based overflow. This vulnerability is tracked as CVE-2026-55556. The attack can be launched remotely. No exploit exists. It is best practice to apply a patch to resolve this issue.

Detailsinfo

A vulnerability has been found in rsyslog (affected version not known) and classified as critical. This vulnerability affects some unknown functionality of the component imhttp Basic Auth. The manipulation with an unknown input leads to a heap-based overflow vulnerability. The CWE definition for the vulnerability is CWE-122. A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc(). As an impact it is known to affect confidentiality, integrity, and availability.

The advisory is available at seclists.org. This vulnerability was named CVE-2026-55556. The exploitation appears to be easy. The attack can be initiated remotely. The technical details are unknown and an exploit is not available.

Applying the patch acde2ba25ea33816694b787859f4a727a247b6d6 is able to eliminate this problem. The bugfix is ready for download at github.com.

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Productinfo

Name

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 6.3
VulDB Meta Temp Score: 6.0

VulDB Base Score: 6.3
VulDB Temp Score: 6.0
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Heap-based overflow
CWE: CWE-122 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Patch
Status: 🔍

0-Day Time: 🔒

Patch: acde2ba25ea33816694b787859f4a727a247b6d6

Timelineinfo

06/30/2026 Advisory disclosed
06/30/2026 +0 days VulDB entry created
06/30/2026 +0 days VulDB entry last update

Sourcesinfo

Product: github.com

Advisory: seclists.org
Status: Confirmed

CVE: CVE-2026-55556 (🔒)
GCVE (CVE): GCVE-0-2026-55556
GCVE (VulDB): GCVE-100-374782

Entryinfo

Created: 06/30/2026 07:13
Changes: 06/30/2026 07:13 (52)
Complete: 🔍
Cache ID: 216::103

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