Skip to content
Fencer Intel
high 8.2

CVE-2026-104635 json

Uncontrolled recursion in elixir-protobuf/protobuf JSON decoding of self-referential messages

published 2026-10-09 31 d ago modified 2026-10-15 25 d ago also EEF-CVE-2026-104635 , EUVD-2026-95562 , GHSA-m497-c2h9-rvw6

cvss
8.2
version 4.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 43%
public exploits
0
none known

Summary

Uncontrolled Recursion vulnerability in Protobuf.JSON.Decode in elixir-protobuf protobuf allows an unauthenticated remote attacker to crash the decoding process via a deeply nested JSON document. Any application that decodes attacker-supplied JSON with Protobuf.JSON.decode/3, Protobuf.JSON.decode!/3, or Protobuf.JSON.from_decoded/3 into a schema that contains a self-referential or cyclic message type is affected.

In lib/protobuf/json/decode.ex, the embedded-message clause of decode_singular/3 recurses into internal_from_json_data/3 once per nesting level without incrementing or checking the decoder's depth counter. The depth guard increase_depth_and_maybe_throw/1 covers only the Google.Protobuf.ListValue and Google.Protobuf.Struct clauses, so the recursion_limit option has no effect on user-defined message types. Each nesting level allocates a stack frame and heap objects, and a sufficiently deep document exhausts the memory of the decoding process. Confidentiality and integrity are not affected.

This issue affects protobuf: from 0.8.0 before 0.17.1.

Patch / fix

  • hex protobuf 0.17.1
  • elixir-protobuf protobuf 0.17.1

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-2026-104635 updated cvss 5.9

protobuf: protobuf: Denial of Service via deeply nested JSON input

  • Red Hat OpenShift Service Mesh 3 istio-proxy-selinux, istio-proxy 1.30.5-1.el9 Red Hat AMQ Clients protobuf 3.19.6-2.el8
    affected: workaround, no fix available “Fix deferred”
  • Red Hat Ansible Automation Platform 2 python-protobuf 4.21.12-1.el9ap
    affected: workaround, no fix planned “Out of support scope”
  • Red Hat Ceph Storage 9 protobuf, protobuf 3.19.6-2.el8 Red Hat Enterprise Linux 7 protobuf-vim, protobuf-java, protobuf-lite, protobuf-emacs, protobuf-python, protobuf-javadoc, +3 more Red Hat Enterprise Linux 8 protobuf, protobuf-lite, python3-protobuf, protobuf-compiler, protobuf 3.19.6-2.el8 Red Hat Enterprise Linux 9 protobuf, protobuf-lite, python3-protobuf, protobuf-compiler, protobuf 3.19.6-2.el8 Red Hat Enterprise Linux 10 protobuf 3.19.6-2.el8 Red Hat OpenShift Container Platform 4 openshift/ose-rhel-coreos-8, openshift/ose-rhel-coreos-9
    +1 more products
    Red Hat OpenShift Container Platform 5 openshift/ose-rhel-coreos-9
    affected: workaround, no fix available “Fix deferred”
  • Red Hat OpenStack Platform 16.2 python3-protobuf, protobuf 3.19.6-2.el8
    affected: workaround, no fix planned “Out of support scope”
  • Red Hat Satellite 6 python-protobuf 4.21.6-5.el8pc, python-protobuf 4.21.12-1.el9ap
    affected: workaround, no fix available “Fix deferred”
  • Red Hat Update Infrastructure 4 for Cloud Providers python-protobuf 4.21.12-1.el9ap
    affected: workaround, no fix planned “Out of support scope”
  • Red Hat Hardened Images protobuf 3.19.6-2.el8
    not affected: component not present

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
25 d ago

Exploit prediction

0.50% chance of exploitation in the next 30 days, higher than 43% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • osv.dev https://osv.dev/vulnerability/EEF-CVE-2026-104635 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 4.0 8.2 CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
CNA 4.0 8.2 CVSS:4.0/AV:N/AC:L/AT:P/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 protobuf
>=0.8.0, <0.17.1
0.17.1

Affected products

  • elixir-protobuf protobuf

Classification

Weakness

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.

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