How severe is GHSA-rm8v-mxj3-5rmq?

No CVSS score has been assigned to GHSA-rm8v-mxj3-5rmq yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by GHSA-rm8v-mxj3-5rmq?

GHSA-rm8v-mxj3-5rmq affects the following packages: github.com/lestrrat-go/jwx/v2 (Go), github.com/lestrrat-go/jwx (Go). Ecosystems affected: Go.

How do I fix GHSA-rm8v-mxj3-5rmq?

Update github.com/lestrrat-go/jwx/v2 to 2.0.11 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-rm8v-mxj3-5rmq is resolved across your whole dependency graph.

How do I detect GHSA-rm8v-mxj3-5rmq in my Go dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/lestrrat-go/jwx/v2, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate GHSA-rm8v-mxj3-5rmq if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Is GHSA-rm8v-mxj3-5rmq actively exploited in the wild?

No public exploit code has been indexed for GHSA-rm8v-mxj3-5rmq yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

When was GHSA-rm8v-mxj3-5rmq published, and has it been updated?

GHSA-rm8v-mxj3-5rmq was published on June 14, 2023 and was last updated on November 8, 2023. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐹 Go

Not in CISA KEV

github.com/lestrrat-go/jwx vulnerable to Potential Padding Oracle AttackGHSA-rm8v-mxj3-5rmq

Fix: lestrrat-go/jwx@6c41e38

GHSA-rm8v-mxj3-5rmq is a security vulnerability in github.com/lestrrat-go/jwx/v2. A fix is available for github.com/lestrrat-go/jwx/v2 — see the affected versions and patch details below.

Also known asGO-2023-1859

Published

Jun 14, 2023

Updated

Nov 8, 2023

Affected

2 pkgs

Patched

2 / 2

Exploits

None indexed

Exploitation data as of Nov 8, 2023 · OSV.dev, FIRST.org (EPSS)

Real-World Exposure

2 pkgs affected

🐹github.com/lestrrat-go/jwx/v2🐹github.com/lestrrat-go/jwx

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.

Description

Summary

Decrypting AES-CBC encrypted JWE has Potential Padding Oracle Attack Vulnerability.

Details

On v2.0.10, decrypting AES-CBC encrypted JWE may return an error "failed to generate plaintext from decrypted blocks: invalid padding":

https://github.com/lestrrat-go/jwx/blob/8840ffd4afc5839f591ff0e9ba9034af52b1643e/jwe/internal/aescbc/aescbc.go#L210-L213

Reporting padding error causes Padding Oracle Attack Vulnerability. RFC 7516 JSON Web Encryption (JWE) says that we MUST NOT do this.

11.5. Timing Attacks To mitigate the attacks described in RFC 3218 [RFC3218], the recipient MUST NOT distinguish between format, padding, and length errors of encrypted keys. It is strongly recommended, in the event of receiving an improperly formatted key, that the recipient substitute a randomly generated CEK and proceed to the next step, to mitigate timing attacks.

In addition, the time to remove padding depends on the length of the padding. It may leak the length of the padding by Timing Attacks.

https://github.com/lestrrat-go/jwx/blob/796b2a9101cf7e7cb66455e4d97f3c158ee10904/jwe/internal/aescbc/aescbc.go#L33-L66

To mitigate Timing Attacks, it MUST be done in constant time.

Impact

The authentication tag is verified, so it is not an immediate attack.

Affected Packages

2 total 2 fixed

Ecosystem	Package	Vulnerable range	Fix
🐹Go	`github.com/lestrrat-go/jwx/v2`	all versions	2.0.11`go get github.com/lestrrat-go/jwx/v2@v2.0.11`
🐹Go	`github.com/lestrrat-go/jwx`	all versions	1.2.26`go get github.com/lestrrat-go/jwx@v1.2.26`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/lestrrat-go/jwx/v2, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/lestrrat-go/jwx/v2 to 2.0.11 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-rm8v-mxj3-5rmq is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Frequently Asked Questions

### Summary Decrypting AES-CBC encrypted JWE has Potential Padding Oracle Attack Vulnerability. ### Details On [v2.0.10](https://github.com/lestrrat-go/jwx/releases/tag/v2.0.10), decrypting AES-CBC encrypted JWE may return an error "failed to generate plaintext from decrypted blocks: invalid padding": https://github.com/lestrrat-go/jwx/blob/8840ffd4afc5839f591ff0e9ba9034af52b1643e/jwe/internal/aescbc/aescbc.go#L210-L213 Reporting padding error causes [Padding Oracle Attack](https://en.wikipedia.org/wiki/Padding_oracle_attack) Vulnerability. RFC 7516 JSON Web Encryption (JWE) says that we

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