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Fencer Vulns
high 8.2

CVE-2026-104635 json

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

published 2026-10-09 30 d ago modified 2026-10-15 24 d ago also EEF-CVE-2026-104635 , GHSA-m497-c2h9-rvw6 , EUVD-2026-95562

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
24 d ago

Exploit prediction

0.50% chance of exploitation in the next 30 days, higher than 43% of all scored CVEs (FIRST EPSS, 2026-11-08).

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 Vulns 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.