CVE-2026-111458: CWE-122 Heap-based Buffer Overflow in adulau ssldump
Description
The fanx_fingerprint function in ssl/sslxprint.c of ssldump allocates a heap buffer for formatting FAN/1 X.509 certificate fingerprints. The allocation size is computed as strlen(b64) + strlen(hex) + 31, but the format string "fan1:x509:server:passive:%s:sha256:%s" contains 33 fixed characters in addition to the two variable-length fields and a null terminator, requiring strlen(b64) + strlen(hex) + 34 bytes. This miscalculation results in a 3-byte heap-based buffer overflow on every invocation of the function with valid inputs. The overflow occurs because sprintf writes the full formatted string into the undersized heap buffer without bounds checking. An attacker who can supply a crafted pcap file containing a TLS X.509 certificate to a user running ssldump with FAN/1 fingerprinting enabled (for example with the -j -N options) can trigger the overflow. The resulting heap corruption may lead to denial of service through a crash or, in a worst-case scenario, arbitrary code execution in the context of the user running ssldump. The vulnerability is deterministic and requires no special privileges beyond the ability to provide input to the tool.
CVSS v4.0
Score 6.8medium
Affected software
adulau
ssldump
cpe:2.3:a:adulau:ssldump:*:*:*:*:*:*:*:*Run 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
The fanx_fingerprint function in ssl/sslxprint.c of ssldump allocates a heap buffer sized as strlen(b64) + strlen(hex) + 31, but the format string requires strlen(b64) + strlen(hex) + 34 bytes. This off-by-three error causes a heap-based buffer overflow when sprintf writes the formatted string into the undersized buffer. An attacker supplying a crafted pcap file with a TLS X.509 certificate can trigger this overflow if ssldump is run with FAN/1 fingerprinting enabled (e.g., with -j -N options). The overflow leads to heap corruption, which may cause a crash or arbitrary code execution in the context of the user running ssldump. The vulnerability is deterministic and requires only the ability to provide input to ssldump.
Potential Impact
Heap corruption caused by the buffer overflow can lead to denial of service via application crash or, in worst cases, arbitrary code execution with the privileges of the user running ssldump. No special privileges are required beyond supplying crafted input to the tool. The vulnerability affects confidentiality, integrity, and availability of the affected system.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, avoid running ssldump with FAN/1 fingerprinting enabled on untrusted input. Restrict usage of ssldump to trusted data sources and consider disabling the vulnerable fingerprinting feature to prevent exploitation.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- CIRCL
- Date Reserved
- 2026-10-16T05:24:32.520Z
- Cvss Version
- 4.0
- State
- PUBLISHED
Threat ID: 6ad1bacd2cdf04f656bb877a
Added to database: 10/16/2026, 05:49:01 UTC
Last enriched: 10/16/2026, 06:03:59 UTC
Last updated: 10/16/2026, 19:03:29 UTC
Views: 15
Community Reviews
0 reviewsCrowdsource mitigation strategies, share intel context, and vote on the most helpful responses. Sign in to add your voice and help keep defenders ahead.
Want to contribute mitigation steps or threat intel context? Sign in or create an account to join the community discussion.
Actions
Updates to AI analysis require Pro Console access. Upgrade inside Console → Billing.
External Links
Need more coverage?
Upgrade to Pro Console for AI refresh and higher limits.
For incident response and remediation, OffSeq services can help resolve threats faster.
Latest Threats
Check if your credentials are on the dark web
Instant breach scanning across billions of leaked records. Free tier available.