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VulnerabilityPublished

CVE-2026-110008: @fastify/oauth2 · Cross-Site Request Forgery (CSRF)

Affects @fastify/oauth2Source CVE Database V5

0

Not known to be exploited · CVSS 4.2 Medium : upgrade to 8.3.2 when convenient.

Data as of 26 Oct 2026, 17:16 UTC

CVSS 3.1 base score
4.2Medium
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.09% chance of exploitation in 30 days – higher than 0% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CISA SSVC
Exploitation
No evidence of active exploitation and no public proof of concept
Automatable
Attackers cannot reliably automate steps 1–4 of the kill chain
Technical impact
Limited control over the software or limited information exposure

CISA SSVC assessment, 2026-10-19.

Patch
Available – fixed in 8.3.2
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 19 Oct 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq 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 26 Oct 2026.

What to do

Upgrade @fastify/oauth2 to 8.3.2.

Affected software

ProductAffectedFixed in
@fastify/oauth2@fastify/oauth2Affected
  • >=7.2.0 <8.3.2
Fixed in
  • 8.3.2
npm@fastify/oauth2pkg:npm/@fastify/oauth2Other threatsAffected
  • >=7.2.0 <8.3.2
Fixed in
  • 8.3.2

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

AI-suggested

Upgrade @fastify/oauth2 to version 8.3.2 or later, where the issue is fixed. As a temporary workaround, explicitly set the cookie Path attribute so that the cookies set and cleared share the same path, ensuring the single-use guarantee of the state cookie is enforced.

Description

@fastify/oauth2 versions 7.2.0 through 8.3.1 contain a Cross-Site Request Forgery (CSRF) vulnerability due to inconsistent cookie Path attributes for state and code-verifier cookies during OAuth2 login flows. This inconsistency allows the state cookie to persist beyond the OAuth callback, violating the single-use guarantee. An attacker who learns a valid state value can perform login CSRF by forcing the victim's browser to sign into the attacker’s account. The issue is fixed in version 8.3.2.

References

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