CVE-2026-126048: Martin Preuss Gwenhywfar · Stack-based Buffer Overflow
Affects Martin Preuss GwenhywfarSource CVE Database V5
Not known to be exploited · CVSS 5.1 Medium : upgrade to 5.14.2 when convenient.
Data as of 10 Nov 2026, 17:19 UTC
Thin evidence
One scorer or none| CNA (VulnCheck) | CVSS 4.0 | 5.1 |
|---|---|---|
| CNA (VulnCheck) | CVSS 3.1 | 4.6 |
- Patch
- Available – fixed in 5.14.2
CVSS:4.0/AV:P/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 10 Nov 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 10 Nov 2026.
What to do
Upgrade Martin Preuss Gwenhywfar to 5.14.2.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| Martin PreussGwenhywfar | Affected
| Fixed in
|
GitHubGwenhywfarpkg:github/GwenhywfarOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
Upgrade Gwenhywfar to version 5.14.2 or later, where this vulnerability is fixed. No other mitigation or temporary workaround is indicated in the available data.
Description
Gwenhywfar versions from 4.99.8beta up to but not including 5.14.2 contain a stack-based buffer overflow vulnerability in the GWEN_TLV_Buffer_To_DB() function. This occurs when decoding BER-TLV tags into a fixed 128-byte buffer, allowing an attacker to crash the application by supplying a record with about 127 or more tag continuation bytes or a truncated multi-byte tag. The vulnerability can be triggered, for example, via a malicious chip card's EF_SSD file read by libchipcard's ZKA driver. The issue is fixed in version 5.14.2.
References
- github.com/aqbanking/gwenhywfar/commit/ed8e2f8cdc27fd5c1b629cf9c1f6b93b2e009757 (opens in a new tab)
- github.com/aqbanking/gwenhywfar/commit/6b50388e6b4a96f02d3d56e1d7747405fa881f39 (opens in a new tab)
- aquamaniac.de/rdm/projects/gwenhywfar/files (opens in a new tab)
- github.com/aqbanking/gwenhywfar/blob/424949d0c6e61028eaccd6e46e4c0c41931c2b2f/src/parser/tlv.c (opens in a new tab)
- vulncheck.com/advisories/gwenhywfar-4.99-8beta-before-5.14.2-stack-buffer-overflow-via-gwen-tlv-buffer-to-db (opens in a new tab)