Immediate
Before a patch is released, reduce exposure immediately and only allow trusted sources to reach the affected service.
root@hackertop:~/vulnfeed/CVE-2026-43864#
CVE-2026-43864
LOW
CVE
⚠ Unpatched · Zero-day◉ PoC 公开
Lifecycle 4/7
mutt up to 2.3.1 show_sig_summary null pointer dereference
LIFECYCLE
2.8
CVSS
Vulnerability Description
A vulnerability, which was classified as problematic, was found in mutt up to 2.3.1 (Mail Client Software). Affected is the function show_sig_summary. Upgrading to version 2.3.2 eliminates this vulnerability.
Root Cause Analysis
CWE is classifying the issue as CWE-476. A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit.
Impact: This is going to have an impact on availability.
Countermeasure: Upgrading to version 2.3.2 eliminates this vulnerability.
Impact: This is going to have an impact on availability.
Countermeasure: Upgrading to version 2.3.2 eliminates this vulnerability.
Validation (PoC/EXP) - Looking for Contributors
No public PoC yet
Public validation traces already exist. Community contributors can extend them with richer reproduction content.
Contribute Your PoC/EXP
Log in to contribute PoC/EXP content. Log in
Mitigation Plan - Sorted by Priority
High
Enable extra access controls, WAF/ACL, or reverse-proxy rules for mutt.
High
Use logs and IOCs to hunt through production traffic and confirm whether exploitation traces already exist.
Medium
Keep this issue on the watch list and follow vendor advisories, rollback notices, and new variants.
Vulnerability Lifecycle - Click each stage to inspect details
The issue has entered HackerTop VulnFeed and is now being tracked by the community.
The vulnerability has been synchronized into the platform and entered the visible triage flow.
Initial impact validation is complete based on current disclosure, technical details, and public intelligence.
A public proof path already exists for reference.
No in-the-wild exploitation has been confirmed yet, but monitoring should continue.
No vendor patch is available yet. Apply temporary mitigations first.
Reduce exposure, restrict access, and inspect logs until a permanent fix is available.
2.8
CVSS
Temp Score
2.8
LOW
Vector String
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Metric Details
Attack Vector
Attack Vector
Network
Attack Complexity
Attack Complexity
Low
Privileges Required
Privileges Required
None
User Interaction
User Interaction
None
Confidentiality Impact
Confidentiality Impact
High
Integrity Impact
Integrity Impact
High
Availability Impact
Availability Impact
High
Back to VulnFeed
CVE-2026-43864 · CVSS 2.8 · Active Threat
