CVE-2026-12547: Libsoup: information disclosure in libsoup via soupauthmanager proxy credential leak on proxy switch

lowCVSS 3.4CVE-2026-12547

CSIRTS triage

vendor: GNOME product: libsoup Information disclosure

What: There is an information disclosure vulnerability in libsoup related to proxy credential leaks.
Who is affected: Applications using libsoup for HTTP requests.
Urgency: Remediation is important to protect sensitive information, with a low severity rating.
Action: Upgrade to the latest version of libsoup that resolves this issue.

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

⚡ Watch libsoup

Get an email when a new libsoup advisory drops — max one per day, one-click unsubscribe.

Details

Source: Microsoft Security Response Center (INTL · vendor-psirt · site)
Severity: low — CVSS 3.4
Published: 2026-07-14
Exploitation: Not in CISA KEV at last sync

Original advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-12547

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-2026-125470.23% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 14% of all scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-12547	coverage & exploitation status	NVD · CVE.org

Same CVEs, other sources

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

lowCVE-2026-12547: SoupAuthManager caches proxy authentication credentials without scoping them to the proxy auth…nvd

Recent advisories for Libsoup

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.

high[UPDATE] [hoch] Red Hat Enterprise Linux (SSSD, libsoup): Mehrere Schwachstellencert-bund · 2026-07-31
mediumCVE-2026-66339: A flaw was found in libsoup. After a CONNECT tunnel is established through an HTTP proxy, libs…nvd · 2026-07-24
mediumCVE-2026-66338: A flaw was found in libsoup. The chunked transfer encoding parser uses a permissive parsing fu…nvd · 2026-07-24
mediumCVE-2026-66337: A flaw was found in libsoup. An unsigned integer underflow in the soup_filter_input_stream_rea…nvd · 2026-07-24
mediumCVE-2026-12548: A heap out-of-bounds read flaw was found in libsoup. When parsing multipart HTTP messages, an …nvd · 2026-07-21
high[UPDATE] [high] Red Hat Enterprise Linux (libsoup): Vulnerability allows information disclosurecert-bund · 2026-07-17