CVE-2026-126048

Description

Gwenhywfar 4.99.8beta before 5.14.2 contains a stack-based buffer overflow in GWEN_TLV_Buffer_To_DB() in src/parser/tlv.c when decoding BER-TLV tags into a fixed 128-byte buffer. Attackers can supply a record with about 127 or more tag continuation bytes or a truncated multi-byte tag, such as via a malicious chip card's EF_SSD file read by libchipcard's ZKA driver, to crash the application.

References

• https://github.com/aqbanking/gwenhywfar/blob/424949d0c6e61028eaccd6e46e4c0c41931c2b2f/src/parser/tlv.c#L629-L655
• https://github.com/aqbanking/gwenhywfar/commit/6b50388e6b4a96f02d3d56e1d7747405fa881f39
• https://github.com/aqbanking/gwenhywfar/commit/ed8e2f8cdc27fd5c1b629cf9c1f6b93b2e009757
• https://www.aquamaniac.de/rdm/projects/gwenhywfar/files
• https://www.vulncheck.com/advisories/gwenhywfar-4.99-8beta-before-5.14.2-stack-buffer-overflow-via-gwen-tlv-buffer-to-db