CVE-2026-55556High· 8.2▾ MidnightPoC availableRsyslog is a rocket-fast system for log processing. From 8.2110.0 until 8.2604.0, the optional imhttp module's parse_auth_header function in contrib/imhttp/imhttp.c allocates a zero-byte heap buffer with calloc(0, len) when an HTTP Basic…
▾ Midnight zone — Critical, or high with PoC / in-the-wild
impact 45.1 · likelihood 0.2 · exploitation 12
A public proof-of-concept already exists for this vulnerability — see Exploit availability below.
Stakeholder-Specific Vulnerability Categorization from CISA's ADP record at CVE.org: whether exploitation is observed, whether an attack can be automated, and how much of the system is at stake. The CVSS score shown above comes from the assigning CNA record, not NVD.
Exploit-prediction probability, daily snapshots since Sep 19.
Disclosure to exploitation, from the record and what we observed since indexing it.
Disclosed via NVD
0.7%
Exploit / PoC code exists
Last analysed / modified upstream
0.7% → 1.1%
Rsyslog is a rocket-fast system for log processing. From 8.2110.0 until 8.2604.0, the optional imhttp module's parse_auth_header function in contrib/imhttp/imhttp.c allocates a zero-byte heap buffer with calloc(0, len) when an HTTP Basic Authorization value exceeds its fixed work buffer, then passes that pointer to apr_base64_decode. An unauthenticated remote attacker can send an oversized encoded credential to an imhttp endpoint configured for Basic Authentication, causing decoded data to overwrite adjacent heap memory before credential validation. Deployments that do not install, load, and use imhttp with Basic Authentication are not affected. The demonstrated impact is a process crash that interrupts log collection, and code execution has not been demonstrated. This issue is fixed in version 8.2604.0.
Refer to the linked advisories for vendor-supplied fixes and affected version ranges.
Field changes observed since this record was first indexed.
Connected by shared product, vendor, weakness, or advisory.
CVE-2026-78002High· 7.5A flaw was found in rsyslog
CVE-2026-61548High· 8.1Rsyslog is a rocket-fast system for log processing
CVE-2026-19654High· 7.5A unauthenticated remote peer may lead rsyslogd to crash due to a flaw in the optional imptcp module
CVE-2025-71436High· 7.1raptor2: raptor2: arbitrary code execution via heap-based buffer overflow in language tag handling (CVE-2025-71436)
CVE-2025-64031Low· 2.5libarchive 3.8.x before 3.8.2 has a strcpy heap-based buffer overflow in the gzip writer via the original-filename field to archive_compressor_gzip_open in archive_write_add_filter_gzip.c, aka GHSA-92wx-p669-8gr9
CVE-2026-92709High· 8.1Rsyslog: DynFile Path Traversal → Arbitrary File Write as Root → RCE