CVE-2025-13034VulnerabilityPublished 6 Jan 2026Updated 28 Oct 2026

When using CURLOPT_PINNEDPUBLICKEY option with libcurl or --pinnedpubkey with the curl tool, curl should check the

Affects curlSource GCVE Database

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Not known to be exploited · CVSS 5.9 Medium : upgrade to 8.14.1-2ubuntu1.1 when convenient.

Data as of 8 Nov 2026, 23:23 UTC

CVSS 3.1 base score

5.9Medium

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

EPSS: 0.2% chance of exploitation in 30 days – higher than 15% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 8.14.1-2ubuntu1.1

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

Attack Vector: Network
Attack Complexity: High
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: High
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: High: A successful attack depends on conditions beyond the attacker's control. That is, a successful attack cannot be accomplished at will, but requires the attacker to invest in some measurable amount of effort in preparation or execution against the vulnerable component before a successful attack can be expected. For example, a successful attack may require an attacker to: gather knowledge about the environment in which the vulnerable target/component exists; prepare the target environment to improve exploit reliability; or inject themselves into the logical network path between the target and the resource requested by the victim in order to read and/or modify network communications (e.g., a man in the middle attack).
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: High: There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to 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 6 Jan 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 8 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

Upgrade the Ubuntu curl package to 8.14.1-2ubuntu1.1.

Patches and advisories

ubuntu.com/security/notices/USN-8062-1 (opens in a new tab)

Affected software

Product	Affected	Fixed in
Ubuntu 25.10curl`pkg:deb/ubuntu/curl?arch=source&distro=questing`Other threats	Affected <8.14.1-2ubuntu1.1	Fixed in 8.14.1-2ubuntu1.1

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

AI-suggested

An official patch is available and should be applied by updating curl to the fixed versions provided by Ubuntu in security notice USN-8062-1. Users should avoid disabling standard certificate verification, especially when using QUIC with ngtcp2 and GnuTLS. Applying the vendor-provided updates will correct the issue and restore proper pinned public key verification.

Description

A vulnerability in curl's CURLOPT_PINNEDPUBLICKEY option allows skipping the public key check of the server certificate under specific conditions. This occurs when using QUIC with ngtcp2 built to use GnuTLS and when standard certificate verification is explicitly disabled by the user. This flaw could allow a connection to proceed without proper verification, potentially enabling a man-in-the-middle attack. The issue affects certain Ubuntu package versions of curl and has a medium severity rating with a CVSS score of 5.9. An official patch is available from Ubuntu to address this vulnerability.

Impact

The vulnerability allows an attacker to bypass the pinned public key verification in curl, potentially enabling a man-in-the-middle attack if the user disables standard certificate verification and uses QUIC with ngtcp2 built with GnuTLS. This could lead to unauthorized interception or manipulation of data transmitted over the affected curl connections. The impact is limited by the requirement that the user must explicitly disable certificate verification and use a specific transport configuration.

Summary

CVE-2025-13034 describes a vulnerability in curl where the CURLOPT_PINNEDPUBLICKEY option or the --pinnedpubkey tool option fails to verify the server's public key under a specific condition. This condition requires the connection to be made using QUIC with ngtcp2 linked against GnuTLS and the user explicitly disabling standard certificate verification. Under these circumstances, curl skips the public key check, allowing connections to potentially an impostor server. The vulnerability was discovered by Stanislav Fort and affects several Ubuntu curl package versions. The issue is fixed in updated Ubuntu packages as per the Ubuntu security notice USN-8062-1.

References

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