Immediate
Before a patch is released, reduce exposure immediately and only allow trusted sources to reach the affected service.
root@hackertop:~/vulnfeed/CVE-2026-43861#
CVE-2026-43861
MEDIUM
CVE
⚠ Unpatched · Zero-day◉ PoC 公开
Lifecycle 4/7
mutt up to 2.3.1 url_pct_decode null byte or nul character
LIFECYCLE
4.3
CVSS
Vulnerability Description
A vulnerability classified as problematic has been found in mutt up to 2.3.1 (Mail Client Software). This affects the function url_pct_decode. Upgrading to version 2.3.2 eliminates this vulnerability.
Root Cause Analysis
CWE is classifying the issue as CWE-158. The product receives input from an upstream component, but it does not neutralize or incorrectly neutralizes NUL characters or null bytes when they are sent to a downstream component.
Impact: This is going to have an impact on confidentiality, integrity, and availability.
Countermeasure: Upgrading to version 2.3.2 eliminates this vulnerability.
Impact: This is going to have an impact on confidentiality, integrity, and 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.
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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.
4.3
CVSS
Temp Score
4.3
MEDIUM
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
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CVE-2026-43861 · CVSS 4.3 · Active Threat
