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CVE-2026-65627VulnerabilityPublished Updated

Improper Handling of Highly Compressed Data (Data Amplification) vulnerability in potatosalad jose (erlang-jose) allows a remote attacker to exhaust a node's memory with a small crafted JWE token

Affects joseSource GCVE Database

0
Authoritative record:CVE-2026-65627· Medium 6.9

Not known to be exploited · CVSS 6.9 Medium.

Data as of 28 Oct 2026, 22:28 UTC

CVSS 4.0 base score
6.9Medium
How severe the flaw is on the 0–10 CVSS scale.
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 26 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

Affected software

ProductAffectedFixed in
Ubuntu 26.10josepkg:deb/ubuntu/jose?arch=source&distro=stonkingOther threatsAffected
  • =14-2build1
  • =14-2build2
Fixed in–
Ubuntu 26.04 LTSjosepkg:deb/ubuntu/jose?arch=source&distro=resoluteOther threatsAffected
  • =14-2build1
Fixed in–
Ubuntu 24.04 LTSjosepkg:deb/ubuntu/jose?arch=source&distro=nobleOther threatsAffected
  • 11-2 – 13-1
5 affected builds
Fixed in–
Ubuntu 22.04 LTSjosepkg:deb/ubuntu/jose?arch=source&distro=jammyOther threatsAffected
  • =10-3
  • =11-2
Fixed in–
Ubuntu 20.04 LTSjosepkg:deb/ubuntu/jose?arch=source&distro=focalOther threatsAffected
  • =10-2build2
Fixed in–
Ubuntu 18.04 LTSjosepkg:deb/ubuntu/jose?arch=source&distro=bionicOther threatsAffected
  • =10-2
  • =10-2build1
Fixed in–

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

Description

Improper Handling of Highly Compressed Data (Data Amplification) vulnerability in potatosalad jose (erlang-jose) allows a remote attacker to exhaust a node's memory with a small crafted JWE token. The jose_jwe_zip:uncompress/2 function in src/jwe/jose_jwe_zip.erl decompresses the DEFLATE-compressed plaintext of a JWE that carries the optional zip: DEF header by calling zlib:inflate/2 on the entire attacker-controlled stream, with no bound on the output size or the inflation ratio. Raw DEFLATE reaches ratios around 1000:1 on highly repetitive input, so a few-kilobyte token inflates to hundreds of megabytes or gigabytes in a single call. Decompression runs automatically during decryption through jose_jwe:block_decrypt/2 (JOSE.JWE.block_decrypt/2 in Elixir), before the recipient can inspect or reject the payload. With the common asymmetric key-management algorithms (RSA-OAEP, ECDH-ES) an attacker needs only the recipient's public key to craft such a token, so no authentication or secret material is required. A single small token can exhaust the node's memory and crash the BEAM, denying service to all users. This issue affects jose: from 1.0.0 before 1.11.13.

References

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