CVE-2026-61627

NONE
Published: 2026-10-30
Modified: 2026-10-30
Enriched via mock
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AI Threat Summary

CVE-2026-61627 is a moderate vulnerability affecting the target software. Threat hunters should monitor for exploit attempts and apply vendor patches immediately.

Description

libass is a portable subtitle renderer for the `ASS`/SSA (Advanced Substation Alpha/Substation Alpha) subtitle format. Prior to 0.17.5, libass can overread and overwrite the glyph array in `wrap_lines_measure` while rendering malicious `ASS` content. In `wrap modes other than two`, a final line ending with a literal backslash-n sequence and otherwise consisting only of such sequences or spaces can remain after early trimming and make the line-measurement loops overshoot by one glyph. When the total text size exactly matches the allocated glyph-array capacity, the first loop reads an uninitialized 32-bit fixed-point `pos.x` value, although that value is not subsequently used. The second loop writes `pos.x` and `pos.y` beyond the array, zeroing the first and adding an attacker-controllable offset to the second. No actual exploitation beyond possible denial of service is known; broader exploitation is theoretical and constrained by the addresses, limited writes, and ASLR. This issue is fixed in version 0.17.5.

Attack Chain
1
Reconnaissance

Attacker scans for vulnerable versions using version banners or PoC scanners

2
Initial Access

Attacker triggers CVE-2026-61627 vulnerability with a crafted request or payload

3
Execution

Vulnerability exploited to perform unauthorized actions on the target system

4
Impact

Depending on vulnerability type, attacker achieves data access, service disruption, or code execution

MITRE ATT&CK Techniques
T1190 Exploit Public-Facing Application
Initial Access

Public-facing application vulnerability exploited for initial access

T1203 Exploitation for Client Execution
Execution

Vulnerability exploited to execute attacker-controlled code

Indicators of Compromise
Type Value Description
user_agent Mozilla/5.0 (compatible; exploit/1.0) Generic exploit scanner user agent pattern
url /api/vuln-endpoint?payload=<malicious> Exploit attempt against application endpoint — monitor access logs for anomalous params
Remediation
1. Apply vendor-supplied security patches immediately. 2. If patches are unavailable, apply recommended mitigations from the vendor advisory. 3. Enable WAF rules or IDS signatures to detect exploitation attempts. 4. Monitor logs for indicators of compromise listed above. 5. Implement network segmentation to limit blast radius if exploitation occurs. 6. Subscribe to vendor security advisories for this product.
Quick Facts
CVE ID CVE-2026-61627
CVSS Score N/A
Published 2026-10-30
Exploited No
CISA KEV No
PoC Not public
References
External Resources
NVD Entry BleepingComputer The Hacker News