VulnerabilityPublished 13 Aug 2026Updated 30 Sep 2026

CVE-2024-53861: Dvc · PyJWT Issuer field partial matches allowed

Affects dvcSource GCVE Database

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Not known to be exploited · CVSS 2.2 Low : upgrade to 3.58.0 when convenient.

Data as of 1 Nov 2026, 11:02 UTC

CVSS 3.1 base score

2.2Low

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

EPSS: 0.8% chance of exploitation in 30 days – higher than 57% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 3.58.0, 8.16.0_2

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

Attack Vector: Network
Attack Complexity: High
Privileges Required: High
User Interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: Low
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: 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: 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: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact on 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 13 Aug 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 1 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 dvc to 3.58.0; parsedmarc to 8.16.0_2.

Affected software

Product	Affected	Fixed in
Homebrewdvc`pkg:brew/dvc`Other threats	Affected >=3.56.0_2 <3.58.0	Fixed in 3.58.0
Homebrewparsedmarc`pkg:brew/parsedmarc`Other threats	Affected >=8.16.0_1 <8.16.0_2	Fixed in 8.16.0_2

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

AI-suggested

A patch is available to fix this issue. Users should upgrade to a fixed version of PyJWT that corrects the issuer claim validation logic. No additional mitigations are required beyond applying the official fix.

Description

A vulnerability in PyJWT's issuer ('iss') claim validation allows partial string matches instead of exact matches due to a type-checking bug introduced in version 2.10.0. This causes tokens with incorrect issuer values that partially match the expected issuer string to be accepted. The signature validation remains intact, limiting the impact.

Impact

The impact is limited because the signature must still be valid for the token to be accepted. However, the incorrect issuer validation could allow tokens with partially matching issuer claims to bypass strict issuer checks, potentially weakening security policies relying on exact issuer matching.

Summary

The vulnerability arises from a change in PyJWT's issuer claim check where the code switched from checking if the issuer is a list to checking if it is a Sequence. Since strings are also Sequences, the 'in' operator performs substring matching rather than exact equality. This allows a token with an 'iss' claim that is a substring of the expected issuer to pass validation incorrectly. A proof-of-concept demonstrates that a token with 'iss' value 'urn:' is accepted when 'urn:expected' is required. The signature verification is still enforced, reducing the risk of exploitation.

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 29 Sep 2026, 05:34 UTC

Technical details

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