CVE-2026-34986: Go JOSE denial of service via panic in JWE decryption

CVE-2026-34986 · Severity: high · CVSS 7.5 · Published 2026-04-06

Go JOSE is a software library used by developers to handle encrypted and signed data, such as login tokens and secure messages. A flaw in how the library processes certain encrypted objects allows an attacker to send a specially crafted message that causes the application to crash. This results in a denial-of-service, potentially taking down critical authentication or data processing services.

Technologies: github.com/go-jose/go-jose/v3 (Go), github.com/go-jose/go-jose/v4 (Go). Vendors: Go.

Quick answers

Is CVE-2026-34986 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-34986 being exploited in the wild.
How severe is CVE-2026-34986?
High severity, with a CVSS score of 7.5, published 6 April 2026.
Which products and versions are affected?
github.com/go-jose/go-jose (Go) SEMVER:introduced=0,last_affected=2.6.3; github.com/go-jose/go-jose/v3 (Go) SEMVER:introduced=0,fixed=3.0.5; github.com/go-jose/go-jose/v4 (Go) SEMVER:introduced=0,fixed=4.1.4.
Is there a fix for CVE-2026-34986?
Yes. github.com/go-jose/go-jose/v3 (Go): upgrade to 3.0.5 or later; github.com/go-jose/go-jose/v4 (Go): upgrade to 4.1.4 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-34986 attacked?
It is attacked over the network, in a software library.
Am I affected by CVE-2026-34986?
Check whether you run github.com/go-jose/go-jose (Go), github.com/go-jose/go-jose/v3 (Go) or github.com/go-jose/go-jose/v4 (Go) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

  • github.com/go-jose/go-jose/v3 (Go): upgrade to 3.0.5 or later
    go get github.com/go-jose/go-jose/v3@v3.0.5
  • github.com/go-jose/go-jose/v4 (Go): upgrade to 4.1.4 or later
    go get github.com/go-jose/go-jose/v4@v4.1.4

Technical details

A vulnerability exists in Go JOSE's JWE decryption logic where the library fails to validate the length of the 'encrypted_key' field when a key wrapping algorithm (ending in 'KW') is specified. Specifically, the 'cipher.KeyUnwrap()' function in 'key_wrap.go' attempts to allocate a slice with a zero or negative length based on the empty field, triggering a Go runtime panic. This is reachable via 'ParseEncrypted', 'ParseEncryptedJSON', or 'ParseEncryptedCompact' followed by a 'Decrypt' call. The issue affects versions prior to 4.1.4 and 3.0.5. Applications are only vulnerable if they include key wrapping algorithms in their list of accepted key algorithms during parsing.

Affected products

  • Go JOSE go-jose/v3 < 3.0.5
  • Go JOSE go-jose/v4 < 4.1.4

Identifiers

  • CVE-2026-34986
  • GHSA-78h2-9frx-2jm8
  • GO-2026-4945

Timeline

  • 2026-03-31: patched: Fixes released in versions 4.1.4 and 3.0.5
  • 2026-03-31: advisory: GitHub Security Advisory published
  • 2026-04-06: disclosed: CVE-2026-34986 published to NVD

References

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