CVE-2023-45128: CSRF Token Reuse Vulnerability

Should you act?

Critical and remotely reachable

No known exploitation yet, but it is network-reachable without credentials. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.

• No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
• EPSS 0.4%, percentile 29: FIRST’s model estimates a 0.4% chance of exploitation activity in the next 30 days, higher than 29% of all scored CVEs (low). EPSS is a probability, not a verdict.
• Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
• Only applies if your dependency tree includes github.com/gofiber/fiber/v2 (Go) < 2.50.0, fixed in 2.50.0. Check your lockfile, including transitive dependencies.

What it is

Fiber is an express inspired web framework written in Go. A Cross-Site Request Forgery (CSRF) vulnerability has been identified in the application, which allows an attacker to inject arbitrary values and forge malicious requests on behalf of a user. This vulnerability can allow an attacker to inject arbitrary values without any authentication, or perform various malicious actions on behalf of an authenticated user, potentially compromising the security and integrity of the application. The vulnerability is caused by improper validation and enforcement of CSRF tokens within the application. This issue has been addressed in version 2.50.0 and users are advised to upgrade. Users should take additional security measures like captchas or Two-Factor Authentication (2FA) and set Session cookies with SameSite=Lax or SameSite=Secure, and the Secure and HttpOnly attributes as defense in depth measures. There are no known workarounds for this vulnerability.

From the GitHub advisory

A Cross-Site Request Forgery (CSRF) vulnerability has been identified in the application, which allows an attacker to inject arbitrary values and forge malicious requests on behalf of a user. This vulnerability can allow an attacker to inject arbitrary values without any authentication, or perform various malicious actions on behalf of an authenticated user, potentially compromising the security and integrity of the application.

Vulnerability Details

The vulnerability is caused by improper validation and enforcement of CSRF tokens within the application. The following issues were identified:

1. Token Injection: For 'safe' methods, the token was extracted from the cookie and saved to storage without further validation or sanitization.

2. Lack of Token Association: The CSRF token was validated against tokens in storage but not associated with a session, nor by using a Double Submit Cookie Method, allowing for token reuse.

Weakness type: CWE-20, CWE-352, CWE-565, CWE-807.

Product: github.com/gofiber/fiber/v2 (Go) · Assigned by: GitHub_M · Published: 2023-10-16

Affected and fixed versions

Severity scores

• Attack vector: network (remotely reachable)
• Attack complexity: low
• Privileges required: none (no login)
• User interaction: none
• Scope: changed (can affect other components)

CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.

Exploitation and urgency

• CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
• CISA SSVC assessment: exploitation none, automatable no, technical impact total.
• FIRST EPSS (model of 2026-10-21): 0.36% probability of exploitation activity in the next 30 days; percentile 29.

Timeline

• 2023-10-16 — CVE record published by GitHub_M
• 2023-10-17 — GitHub-reviewed advisory GHSA-94w9-97p3-p368 published (critical)
• 2024-09-16 — CVE record last updated

Sources and references

Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.

Vulnerability records

1. GitHub Advisory GHSA-94w9-97p3-p368 github.com
2. CVE.org record CVE-2023-45128 cve.org
3. NVD entry CVE-2023-45128 nvd.nist.gov

Other references from the CVE record and advisory

1. github.com github.com
2. github.com github.com
3. github.com github.com

Critical Go advisories · Today’s Security Digest