CVE-2026-126049
Gwenhywfar 5.14.2 Use-After-Free via GWEN_TLV_Buffer_To_DB() Nested BER-TLV Parsing
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.
Fixes and workarounds
Fix
The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches.
Source: CNA: VulnCheckFix
The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches.
Source: CNA: VulnCheckAffected products and versions
| Product | Versions | Authority |
|---|---|---|
| Gwenhywfar Martin Preuss aqbanking/gwenhywfar
github |
≥ 5.14.2; < 5.14.3 (affected, custom)
Other versions: unaffected |
CNA: VulnCheck |
Version ranges are source assertions. Check the vendor advisory and your installed configuration before determining exposure.
CVSS assessments
| Version / score | Vector | Authority |
|---|---|---|
| 4.0 / 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:N | CNA: VulnCheck |
| 3.1 / 4.6 medium |
CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H | CNA: VulnCheck |
Exploit evidence
No exploit evidence in collected sources. This is not proof of no exploitation.
References
- https://github.com/aqbanking/gwenhywfar/commit/828b34135dfa33fc347a2929caa2f079ffb00738CNA: VulnCheck · patch
- https://github.com/aqbanking/gwenhywfar/commit/dc8b80945e877f5bdf2d2ae1b50c928c15e990b0CNA: VulnCheck · release-notes, patch
- https://www.aquamaniac.de/rdm/projects/gwenhywfar/filesCNA: VulnCheck · product
- https://github.com/aqbanking/gwenhywfar/blob/f5c3f9dc56aa20cab85fd149885474239cf68632/src/parser/tlv.c#L651-L672CNA: VulnCheck · technical-description
- https://www.vulncheck.com/advisories/gwenhywfar-5.14.2-use-after-free-via-gwen-tlv-buffer-to-db-nested-ber-tlv-parsingCNA: VulnCheck · third-party-advisory
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