# CVE-2026-95393: Wireshark CSN.1 dissector heap buffer overflow

Source: https://junglewise.ai/threats/cve-2026-95393-csn-1-protocol-dissector-crash-in-4-6-0-to-4-6-8-and-4-4-0-to-4-4  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-29. Updated: 2026-09-29  
License: CC BY 4.0 with a link back

CVE-2026-95393 · Severity: medium · CVSS 4.7 · Published 2026-09-29

Wireshark, a network traffic analyzer, contains a heap buffer overflow in its CSN.1 protocol dissector that can be triggered by a malformed network packet or pcap file. An attacker can craft a packet to overflow a buffer without size validation, causing Wireshark to crash or potentially execute arbitrary code. The vulnerability requires no authentication and affects all desktop installations with default GSM protocol support enabled.

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

## Quick answers

**Is CVE-2026-95393 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-95393 being exploited in the wild.

**How severe is CVE-2026-95393?** Medium severity, with a CVSS score of 4.7, published 29 September 2026.

**Which products and versions are affected?** Wireshark Foundation Wireshark 4.4.0 to 4.4.18, 4.6.0 to 4.6.8.

**Is there a fix for CVE-2026-95393?** A patch was published on 2026-09-29: Fixed in Wireshark 4.6.9 and 4.4.19 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-95393 attacked?** It is attacked over the network, in a web application.

**Am I affected by CVE-2026-95393?** Check whether you run Wireshark Foundation 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

A heap out-of-bounds write occurs in the CSN_RECURSIVE_ARRAY handler (packet-csn1.c, csnStreamDissector) which writes elements to a fixed-size destination array without capacity checking. The vulnerable code stores decoded bitstream elements directly to memory before validating remaining buffer length. An attacker supplies crafted GSMTAP packets with Packet Measurement Order messages containing controlled-length element sequences that overflow 97420-byte RlcMacDownlink structures, with element #1408 writing the first byte past allocation bounds.

## Affected products

- Wireshark Foundation Wireshark 4.4.0 to 4.4.18, 4.6.0 to 4.6.8

## Timeline

- 2026-09-23: disclosed
- 2026-09-29: patched: Fixed in Wireshark 4.6.9 and 4.4.19

## References

- [https://gitlab.com/wireshark/wireshark/-/work_items/21510](https://gitlab.com/wireshark/wireshark/-/work_items/21510)
- [https://www.wireshark.org/security/wnpa-sec-2026-99.html](https://www.wireshark.org/security/wnpa-sec-2026-99.html)

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