USN-8550-1: libslirp vulnerability

unknownCVE-2026-9539

It was discovered that libslirp incorrectly handled TCP urgent data. A privileged attacker inside a guest VM could possibly use this issue to obtain sensitive information from the host process memory.

CSIRTS triage

vendor: libslirp product: libslirp Information disclosure

What: libslirp incorrectly handled TCP urgent data, potentially exposing sensitive information.
Who is affected: Privileged attackers inside a guest VM using libslirp.
Urgency: Remediation is important to prevent information disclosure.
Action: Users should apply updates to libslirp to mitigate this issue.

AI-assisted analysis generated from the source advisory — verify against the original.

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Details

Source: Ubuntu Security Notices (INTL · vendor-psirt · site)
Severity: unknown
Published: 2026-07-15
Exploitation: Not in CISA KEV at last sync

Original advisory: https://ubuntu.com/security/notices/USN-8550-1

Exploitation outlook

EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

Low exploitation riskCVE-2026-95390.11% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 1% of all scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-9539	coverage & exploitation status	NVD · CVE.org

Same CVEs, other sources

How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.

mediumCVE-2026-9539: libslirp TCP URG OOB Read Information Leakmsrc