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Vulnerability details: VCID-vqka-wrgj-77eg
Vulnerability ID VCID-vqka-wrgj-77eg
Aliases CVE-2025-30144
GHSA-gm45-q3v2-6cf8
Summary fast-jwt provides fast JSON Web Token (JWT) implementation. Prior to 5.0.6, the fast-jwt library does not properly validate the iss claim based on the RFC 7519. The iss (issuer) claim validation within the fast-jwt library permits an array of strings as a valid iss value. This design flaw enables a potential attack where a malicious actor crafts a JWT with an iss claim structured as ['https://attacker-domain/', 'https://valid-iss']. Due to the permissive validation, the JWT will be deemed valid. Furthermore, if the application relies on external libraries like get-jwks that do not independently validate the iss claim, the attacker can leverage this vulnerability to forge a JWT that will be accepted by the victim application. Essentially, the attacker can insert their own domain into the iss array, alongside the legitimate issuer, and bypass the intended security checks. This issue is fixed in 5.0.6.
Status Published
Exploitability None
Weighted Severity None
Risk None
Affected and Fixed Packages Package Details
Weaknesses (4)
No exploits are available.
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N Found at https://datatracker.ietf.org/doc/html/rfc7519#page-9
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

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low

none

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low

none


Vector: SSVCv2/E:P/A:N/T:P/P:M/B:A/M:M/D:T/2025-03-19T18:29:09Z/ Found at https://datatracker.ietf.org/doc/html/rfc7519#page-9
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N Found at https://github.com/nearform/fast-jwt
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

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none

Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N Found at https://github.com/nearform/fast-jwt/commit/cc26b1d473f900446ad846f8f0b10eb1c0adcbdd
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none


Vector: SSVCv2/E:P/A:N/T:P/P:M/B:A/M:M/D:T/2025-03-19T18:29:09Z/ Found at https://github.com/nearform/fast-jwt/commit/cc26b1d473f900446ad846f8f0b10eb1c0adcbdd
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N Found at https://github.com/nearform/fast-jwt/security/advisories/GHSA-gm45-q3v2-6cf8
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none


Vector: SSVCv2/E:P/A:N/T:P/P:M/B:A/M:M/D:T/2025-03-19T18:29:09Z/ Found at https://github.com/nearform/fast-jwt/security/advisories/GHSA-gm45-q3v2-6cf8
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N Found at https://nvd.nist.gov/vuln/detail/CVE-2025-30144
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none

Exploit Prediction Scoring System (EPSS)
Percentile 0.84525
EPSS Score 0.02126
Published At June 11, 2026, 12:55 p.m.
Date Actor Action Source VulnerableCode Version
2026-06-11T16:57:11.961534+00:00 Vulnrichment Import https://github.com/cisagov/vulnrichment/blob/develop/2025/30xxx/CVE-2025-30144.json 38.6.0