CVE-2026-9079: libcurl had a flaw that when instructed to clear proxy authentication credentials which made it not do so, leaving the old credentials around to get used for subsequent transfers t

criticalCVSS 9.8CVE-2026-9079

libcurl had a flaw that when instructed to clear proxy authentication credentials which made it not do so, leaving the old credentials around to get used for subsequent transfers that should not know nor use them.

Details

Source: NVD Recent CVEs (US · database · site)
Severity: critical — CVSS 9.8
Published: 2026-07-03
Last updated: 2026-07-07
Exploitation: Not in CISA KEV at last sync

Original advisory: https://nvd.nist.gov/vuln/detail/CVE-2026-9079

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.

Moderate exploitation riskCVE-2026-90791.1% 30-day exploitation probability. Patch within normal cadence, watch for KEV listing. Riskier than 61% of all scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-9079	coverage & exploitation status	NVD · CVE.org

Same CVEs, other sources

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

medium[UPDATE] [medium] cURL: Multiple vulnerabilitiescert-bund
unknownCVE-2026-9079: stale proxy password leakmsrc
unknownMultiple vulnerabilities in cURL and libcurl (June 24, 2026)cert-fr-avis

Recent advisories for libcurl had a

A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.

highCVE-2026-9547: When a libcurl-based application performs transfers via `SCP://` or `SFTP://` and utilizes the …nvd · 2026-07-03
highCVE-2026-9546: A vulnerability in libcurl caused the HTTP `Referer:` header to persist even when explicitly cl…nvd · 2026-07-03
highCVE-2026-9545: In this scenario, libcurl first uses a proper HTTP/3 server for the initial transfers, and when…nvd · 2026-07-03
highCVE-2026-9080: Calling `curl_easy_pause()` within the event-based `CURLMOPT_SOCKETFUNCTION` callback triggers …nvd · 2026-07-03
highCVE-2026-8932: libcurl would reuse a previously created connection even when some mTLS config related option h…nvd · 2026-07-03
criticalCVE-2026-8927: When reusing a libcurl handle for sequential transfers driven by environment-variable proxy con…nvd · 2026-07-03