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Fencer Intel
medium 6.9

CVE-2026-65627 json

Decompression bomb via unbounded zlib:inflate in jose_jwe_zip:uncompress/2

published 16d ago modified 9d ago also EEF-CVE-2026-65627 , EUVD-2026-110306 , GHSA-wfpv-qxp8-x5gm

cvss
6.9
version 4.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 16%
public exploits
0
none known

Summary

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.

Patch / fix

  • hex jose 1.11.13
  • potatosalad jose 1.11.13
  • erlang-jose Debian 14 1.11.13-1

debian advisories DEBIAN-CVE-2026-65627

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-65627 updated cvss 7.5

jose: jose: Denial of Service via unbounded decompression of crafted JWE tokens

  • Red Hat Hardened Images rabbitmq-server4.2 4.2.9-0.3.hum1
    affected: workaround, no fix planned “Will not fix”
  • Red Hat Hardened Images grafana13.1 13.1.8-0.4.hum1, grafana13.2 13.2.4-0.3.hum1, grafana12.4 12.4.13-0.4.hum1, rabbitmq-server4.3 4.3.7-0.1.hum1, rabbitmq-server4.3 4.3.7-0.2.hum1
    fixed: vendor fix RHSA-2026:90388
  • Red Hat OpenStack Platform 17.1 rabbitmq-server Red Hat OpenStack Platform 18.0 rabbitmq-server
    not affected: vulnerable code not in execute path

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
9d ago

Exploit prediction

0.25% chance of exploitation in the next 30 days, higher than 16% of all scored CVEs (FIRST EPSS, 2026-11-11).

Exploits and checks

  • github.com https://github.com/potatosalad/erlang-jose/security/advisories/GHSA-wfpv-qxp8-x5gm referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 4.0 6.9 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
CNA 4.0 6.9 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affected packages

ecosystem package affected fixed in
hex jose
>=1.0.0, <1.11.13
1.11.13

Affected products

  • potatosalad jose

Classification

Weakness
  • CWE-409 Improper Handling of Highly Compressed Data (Data Amplification)

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

The maintainers of potatosalad/erlang-jose published their own advisory on GitHub. Reviewed sources take precedence over it.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.