ELEVATED 1 min read 27 Sep 2026

Multiple vulnerabilities in curl Leads Today's Security Review

Threat Level: Elevated Tags: cve-2026-13608, cve-2026-18924, cve-2026-80229, cve-2026-80230, cve-2026-80255, cve-2026-82209, cve-2026-8927, cwe-416, security-brief, ubuntu-com

Key findings
01
Multiple vulnerabilities in curl
CRITICAL
Eunsoo Kim discovered that curl incorrectly handled SASL negotiation for LDAP authentication in certain circumstances. A machine-in-the-middle attacker could possibly use this issue to bypass peer validation. The assigned identifier is CVE-2026-18924.

Executive assessment

Today's brief leads with Multiple vulnerabilities in curl. The single selected finding retains its own technical scope, action, observed status, and evidence limits.

Panel synthesis: Finding 01 leads because it is the only finding today and is rated CRITICAL, with fixed Ubuntu curl packages listed across the affected releases. Themes: curl vulnerabilities; Ubuntu package updates; interim protocol hardening. Patch order: Finding 01 (Act first because it is rated CRITICAL and fixed Ubuntu curl packages are listed; exploitation is unknown, with interim controls limited to avoiding LDAP without TLS, disabling HTTP/2 server push, and keeping standard peer verification enabled when using CURLOPT_PINNEDPUBLICKEY).

Finding 01 — Multiple vulnerabilities in curl

What changed: Eunsoo Kim discovered that curl incorrectly handled SASL negotiation for LDAP authentication in certain circumstances. A machine-in-the-middle attacker could possibly use this issue to bypass peer validation.

Technical evidence: CVE-2026-18924; CVSS v3.1 9.1; weakness CWE-416; technical confidence High.

Why it matters: The Critical priority moves this beyond routine tracking and requires exposure validation, remediation, and compromise assessment.

Observed status: Observed in-the-wild exploitation status is unknown.

Analyst note: Until patching, avoid LDAP without TLS, disable HTTP/2 server push, and keep standard peer verification enabled when using CURLOPT_PINNEDPUBLICKEY. For OpenSSL 3 provider transfers, enable CURLOPT_FORBID_REUSE; disable cookies, and avoid reusing handles when changing proxies. ([curl.se](https://curl.se/docs/CVE-2026-13608.html), [curl.se](https://curl.se/docs/CVE-2026-18924.html), [curl.se](https://curl.se/docs/CVE-2026-80229.html), +5 more)

Fix: Ubuntu curl packages: 26.04 LTS 8.18.0-1ubuntu2.7; 24.04 LTS 8.5.0-2ubuntu10.15; 22.04 LTS 7.81.0-1ubuntu1.29; 20.04 LTS 7.68.0-1ubuntu2.25+esm9; 18.04 LTS 7.58.0-2ubuntu3.24+esm14. ([ubuntu.com](https://ubuntu.com/security/notices/USN-8820-1))

Action: Map CVE-2026-18924 to owned assets, confirm the affected and fixed versions in the cited source, deploy the applicable remediation, and retain evidence of the exposure decision.

[Evidence source: ubuntu.com](https://ubuntu.com/security/notices/USN-8820-1)

cve-2026-13608cve-2026-18924cve-2026-80229cve-2026-80230cve-2026-80255cve-2026-82209cve-2026-8927cwe-416security-briefubuntu-com

Act on this brief

Map detection coverage gaps for the techniques above, or generate Sigma rules from the named CVEs.