# CVE-2026-76924: Wireshark Kerberos dissector heap buffer overflow

Source: https://junglewise.ai/threats/cve-2026-76924-wireshark-kerberos-dissector-heap-buffer-overflow  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-08-19. Updated: 2026-09-25  
License: CC BY 4.0 with a link back

CVE-2026-76924 · Severity: medium · CVSS 5.5 · Published 2026-08-19

Wireshark is a widely used network analysis tool that includes support for decoding the Kerberos authentication protocol. A malformed Kerberos credential packet can trigger an out-of-bounds read in the dissector's key formatting logic, causing Wireshark or TShark to crash. An attacker can exploit this by injecting a crafted packet on the network or tricking a user into opening a malicious packet capture file, resulting in denial of service.

Technologies: [Wireshark](https://junglewise.ai/threats/technologies/wireshark). Vendors: [Wireshark](https://junglewise.ai/threats/vendors/wireshark).

## Quick answers

**Is CVE-2026-76924 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-76924 being exploited in the wild.

**How severe is CVE-2026-76924?** Medium severity, with a CVSS score of 5.5, published 19 August 2026.

**Which products and versions are affected?** Wireshark 4.6.0 to 4.6.7, 4.4.0 to 4.4.17.

**Is there a fix for CVE-2026-76924?** A patch was published on 2026-08-19: Fixed in versions 4.6.8, 4.4.18, and later Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-76924 attacked?** It is attacked over the network.

**Am I affected by CVE-2026-76924?** Check whether you run Wireshark at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

The vulnerability is a heap buffer overflow (CWE-125) in the Kerberos dissector's encryption key handling code, specifically in the learned-key formatter in packet-kerberos-template.c and packet-kerberos.c. When processing a plaintext EncKrbCredPart structure with a short EncryptionKey (1–3 bytes), the dissector correctly copies the key bytes into retained storage but then attempts to format a four-byte hexadecimal preview directly from the original input buffer without bounds checking. This causes an out-of-bounds read beyond the allocated buffer. The attack requires only a crafted plaintext Kerberos credential sent over UDP/88 (no authentication, valid key, or successful decryption needed). An instrumented Wireshark or TShark instance will crash; behavior in release builds depends on adjacent allocator contents. Patches are available in Wireshark 4.6.8, 4.4.18, and later.

## Affected products

- Wireshark Wireshark 4.6.0 to 4.6.7, 4.4.0 to 4.4.17

## Timeline

- 2026-08-12: disclosed
- 2026-08-19: patched: Fixed in versions 4.6.8, 4.4.18, and later

## References

- [https://gitlab.com/wireshark/wireshark/-/work_items/21449](https://gitlab.com/wireshark/wireshark/-/work_items/21449)
- [https://www.wireshark.org/security/wnpa-sec-2026-78.html](https://www.wireshark.org/security/wnpa-sec-2026-78.html)

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