November 14, 2026

CVE Watchtower

CVE-2026-126048Martin Preuss Gwenhywfar Stack-based Buffer Overflow

NVD

Vulnerability Summary

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.
Severity Level
MEDIUM(5.1)
Published Date
Nov 10, 2026
Last Modified
Nov 10, 2026
Exploitation Status
No confirmed exploitation yet
EPSS Score (30-Day)
0.22%Probability
Root Weakness (CWE)
CWE-121: Stack-based Buffer Overflow ↗
The buffer being overwritten is allocated on the stack.
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:N
Attack 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:H
Attack VectorPhysical
Attack ComplexityLow
Privileges RequiredNone
User InteractionNone
ScopeUnchanged
ConfidentialityNone
IntegrityNone
AvailabilityHigh

Affected & Patched Versions

Affected Versions
  • Martin Preuss Gwenhywfar >= 4.99.8beta and < 5.14.2
Patched Versions
  • Martin Preuss Gwenhywfar 5.14.2

What to do

Fix it during your normal patch cycle. No exploitation is confirmed yet.

  1. Check whether you run Martin Preuss Gwenhywfar and which version.
  2. Update to a patched version listed above, then confirm the new version.

Timeline

  • Nov 10, 2026Published
  • Nov 10, 2026Record last modified

Score, severity and exploitation changes are tracked from the day Watchtower started logging them.

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External References

Data last checked: Nov 14, 2026 02:13 UTC