CVE-2026-126049Martin Preuss Gwenhywfar Use After Free
NVD
Vulnerability Summary
Gwenhywfar 5.14.2 contains a heap use-after-free vulnerability in GWEN_TLV_Buffer_To_DB() in src/parser/tlv.c, which frees a nested record's GWEN_DB node when parsing of its contents fails but continues processing and adds the freed node to the parent instead of returning. Attackers can supply a constructed BER-TLV record with unparseable contents, such as via a malicious chip card read by libchipcard, to corrupt heap memory.
CVSS v4.0 Base Metrics — Score 5.1 (MEDIUM)
CVSS:4.0/AV:P/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:NAttack VectorPhysical
Attack ComplexityLow
Attack RequirementsNone
Privileges RequiredNone
User InteractionNone
Confidentiality (Vulnerable System)None
Integrity (Vulnerable System)None
Availability (Vulnerable System)High
Confidentiality (Subsequent System)None
Integrity (Subsequent System)None
Availability (Subsequent System)None
Show CVSS v3.x metrics (score 4.6)
CVSS v3.1 Base Metrics — Score 4.6 (MEDIUM)
CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HAttack VectorPhysical
Attack ComplexityLow
Privileges RequiredNone
User InteractionNone
ScopeUnchanged
ConfidentialityNone
IntegrityNone
AvailabilityHigh
Affected & Patched Versions
- Martin Preuss Gwenhywfar >= 5.14.2 and < 5.14.3
- Martin Preuss Gwenhywfar 5.14.3
What to do
Fix it during your normal patch cycle. No exploitation is confirmed yet.
- Check whether you run Martin Preuss Gwenhywfar and which version.
- Update to a patched version listed above, then confirm the new version.
Timeline
- Nov 10, 2026Published
- Nov 13, 2026Record last modified
Score, severity and exploitation changes are tracked from the day Watchtower started logging them.
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Set up CVE alertsExternal References
- Patchhttps://github.com/aqbanking/gwenhywfar/commit/828b34135dfa33fc347a2929caa2f079ffb00738
- Patchhttps://github.com/aqbanking/gwenhywfar/commit/dc8b80945e877f5bdf2d2ae1b50c928c15e990b0
- Referencehttps://www.aquamaniac.de/rdm/projects/gwenhywfar/files
- Referencehttps://github.com/aqbanking/gwenhywfar/blob/f5c3f9dc56aa20cab85fd149885474239cf68632/src/parser/tlv.c#L651-L672
- Referencehttps://www.vulncheck.com/advisories/gwenhywfar-5.14.2-use-after-free-via-gwen-tlv-buffer-to-db-nested-ber-tlv-parsing
Data last checked: Nov 14, 2026 02:13 UTC