VulnerabilityPublished 21 Jul 2026Updated 3 Nov 2026

CVE-2026-12547: Libsoup2.4 · SoupAuthManager caches proxy authentication credentials without scoping them to the proxy

Affects libsoup2.4Source GCVE Database

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Authoritative record:CVE-2026-12547· Low 3.4

Not known to be exploited · CVSS 3.4 Low.

Data as of 3 Nov 2026, 23:14 UTC

CVSS 3.1 base score

3.4Low

How severe the flaw is on the 0–10 CVSS scale.

CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:N/A:N

Attack Vector: Network
Attack Complexity: Low
Privileges Required: High
User Interaction: Required
Scope: Changed
Confidentiality: Low
Integrity: None
Availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: High: The attacker is authorized with (i.e., requires) privileges that provide significant (e.g., administrative) control over the vulnerable component that could affect component-wide settings and files.
User Interaction: Required: Successful exploitation of this vulnerability requires a user to take some action before the vulnerability can be exploited.
Scope: Changed: An exploited vulnerability can affect resources beyond the security scope managed by the security authority of the vulnerable component. In this case, the vulnerable component and the impacted component are different and managed by different security authorities.
Confidentiality: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the impacted component.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 21 Jul 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 3 Nov 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Affected software

Product	Affected	Fixed in
Ubuntu 26.10libsoup2.4`pkg:deb/ubuntu/libsoup2.4?arch=source&distro=stonking`Other threats	Affected =2.74.3-10.1ubuntu5	Fixed in–
Ubuntu 26.10libsoup3`pkg:deb/ubuntu/libsoup3?arch=source&distro=stonking`Other threats	Affected =3.6.6-1 =3.6.6-1ubuntu3 =3.6.6-1ubuntu3.1	Fixed in–
Ubuntu 26.04 LTSlibsoup3`pkg:deb/ubuntu/libsoup3?arch=source&distro=resolute`Other threats	Affected 3.6.5-4 – 3.6.6-1ubuntu0.2 8 affected builds	Fixed in–
Ubuntu Pro 26.04 LTSlibsoup2.4`pkg:deb/ubuntu/libsoup2.4?arch=source&distro=esm-apps/resolute`Other threats	Affected 2.74.3-10.1ubuntu4 – 2.74.3-10.1ubuntu5+esm4 6 affected builds	Fixed in–
Ubuntu 24.04 LTSlibsoup2.4`pkg:deb/ubuntu/libsoup2.4?arch=source&distro=noble`Other threats	Affected 2.74.3-1 – 2.74.3-6ubuntu1.10 16 affected builds	Fixed in–
Ubuntu 24.04 LTSlibsoup3`pkg:deb/ubuntu/libsoup3?arch=source&distro=noble`Other threats	Affected 3.4.2-4 – 3.4.4-5ubuntu0.10 17 affected builds	Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

Description

SoupAuthManager caches proxy authentication credentials without scoping them to the proxy authority (host:port). When the proxy configuration changes (e.g., via system settings or WPAD), cached Proxy-Authorization headers from the previous proxy are sent to the new proxy, leaking credentials.

References

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