# CVE-2026-76919: Wireshark ESS protocol dissector crash via uninitialized pointer

Source: https://junglewise.ai/threats/cve-2026-76919-wireshark-ess-protocol-dissector-crash-via-uninitialized-pointer  
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-2026-76919 · Severity: medium · CVSS 5.3 · Published 2026-08-19

Wireshark is a widely-used network packet analyzer that includes support for the ESS (Estimated System Services) security protocol. A flaw in its ESS dissector can cause the application to crash when processing malformed packets, disrupting network troubleshooting and analysis operations. An attacker could exploit this by sending a crafted packet over the network or through a malicious packet capture file.

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

## Quick answers

**Is CVE-2026-76919 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-76919 being exploited in the wild.

**How severe is CVE-2026-76919?** Medium severity, with a CVSS score of 5.3, 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-2026-76919?** A patch was published on 2026: Fixed in versions 4.6.8 and 4.4.18 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-76919 attacked?** It is attacked over the network.

**Am I affected by CVE-2026-76919?** 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 use of an uninitialized variable (CWE-457) in the ESS protocol dissector code. Three BIT STRING overrides in the dissector template (ess.cnf) declare a pointer variable without initialization, then pass it to post-processing functions regardless of whether the BER bitstring parsing succeeded. When the dissect_ber_bitstring() helper encounters a malformed BIT STRING (e.g., zero-length), it returns early without assigning the output pointer, leaving it uninitialized. The subsequent call to ess_dissect_attribute_flags() dereferences this uninitialized pointer through TVB APIs, causing a crash or memory access violation. The vulnerability is reachable through registered OID dissectors for CMS/S/MIME content in untrusted network captures or packet files. 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: patched: Fixed in versions 4.6.8 and 4.4.18

## References

- [https://gitlab.com/wireshark/wireshark/-/work_items/21467](https://gitlab.com/wireshark/wireshark/-/work_items/21467)
- [https://www.wireshark.org/security/wnpa-sec-2026-86.html](https://www.wireshark.org/security/wnpa-sec-2026-86.html)

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