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Back to active CVEs
High · CVSS 8.2CVE-2026-65634

Superlinear CPU denial of service in Erlang/OTP ASN.1 OBJECT IDENTIFIER decoderCVE-2026-65634

Answer in brief

CVE-2026-65634 records a High severity (CVSS 8.2) vulnerability in Superlinear CPU denial of service in Erlang/OTP ASN.1 OBJECT IDENTIFIER decoder. The current sources do not mark it as known exploited. The current feed maps Erlang/erlang/otp (generic), Erlang/OTP (generic), Erlang/OTP (generic), Erlang/OTP (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Sep 22, 2026Updated Sep 24, 2026Source checked Nov 6, 2026First seen by HOL Sep 22, 2026Material review Sep 24, 2026
Upstream Advisory

Key facts

Risk
High · CVSS 8.2
Exploitation
Not marked as known exploited
Affected software
4 mapped packages or products
Fix availability
Available

Why this deserves its current priority

CVSS is 8.2. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps Erlang/erlang/otp (generic), Erlang/OTP (generic), Erlang/OTP (generic), Erlang/OTP (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
PackageAffected rangeFixed version
Erlang/erlang/otpgeneric>=84adefa331c4159d432d22840663c38f155cd4c1 <0fe2c02fdc06fab1c63be9db1a7456993d20f8380fe2c02fdc06fab1c63be9db1a7456993d20f838
Erlang/OTPgeneric>=17.0 <**
Erlang/OTPgeneric>=3.0 <**
Erlang/OTPgeneric>=84adefa331c4159d432d22840663c38f155cd4c1 <0fe2c02fdc06fab1c63be9db1a7456993d20f8380fe2c02fdc06fab1c63be9db1a7456993d20f838

Recommended response

  1. 1Check inventory. Check lockfiles and deployed manifests for Erlang/erlang/otp, Erlang/OTP, Erlang/OTP.
  2. 2Review the reported fix. Update Erlang/erlang/otp to 0fe2c02fdc06fab1c63be9db1a7456993d20f838; Erlang/OTP to *; Erlang/OTP to *; Erlang/OTP to 0fe2c02fdc06fab1c63be9db1a7456993d20f838 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

  1. Published upstream

    Sep 22, 2026

    Evidence: source:cvelist:source_dates:source-dates:record
  2. Source modified

    Sep 24, 2026

    Evidence: source:cvelist:source_dates:source-dates:record
  3. First seen by HOL

    Sep 22, 2026

Sources and claim methodology

  • Source referencecna.erlef.org
  • GitHub security advisorygithub.com
  • GitHub security advisorygithub.com
  • Source referenceosv.dev
  • Source referenceerlang.org
Upstream source description

Inefficient algorithmic complexity in the Erlang/OTP asn1 OBJECT IDENTIFIER decoder allows a remote unauthenticated attacker to cause denial of service by sending a crafted OID during the TLS handshake. The BER OID decoder asn1rtt_ber:dec_subidentifiers/3 in lib/asn1/src/asn1rtt_ber.erl and the equivalent PER helper asn1rtt_per_common:dec_subidentifiers/3 in lib/asn1/src/asn1rtt_per_common.erl accumulate a base-128 subidentifier into an unbounded integer using (Av bsl 7) + H per continuation byte. Each shift and addition on the growing accumulator is linear in the number of bits already accumulated, giving quadratic total work in the size of a single subidentifier. The JER helper asn1rtt_jer:json2oid/1 in lib/asn1/src/asn1rtt_jer.erl exhibits the same class of unbounded-integer parsing when decoding a dot-separated OID from JSON. A DER-encoded OBJECT IDENTIFIER with one very large arc (approximately 262 KB of continuation bytes) consumes roughly 13 seconds of CPU on typical hardware. The vulnerable decoder is generated into every ASN.1 module that contains an OBJECT IDENTIFIER, including OTP-PUB-KEY which is reached during X.509 certificate parsing via public_key:pkix_decode_cert/2. This decoder runs before any signature or trust chain verification, so any Erlang service that parses peer TLS certificates is exposed: the default for TLS clients (which always parse the server certificate) and for mutual-TLS servers (which parse client certificates). This vulnerability is associated with program files lib/asn1/src/asn1rtt_ber.erl, lib/asn1/src/asn1rtt_per_common.erl and lib/asn1/src/asn1rtt_jer.erl and program routines asn1rtt_ber:dec_subidentifiers/3, asn1rtt_per_common:dec_subidentifiers/3 and asn1rtt_jer:json2oid/1. This issue affects OTP from OTP 17.0 before OTP 27.3.4.18, OTP 28.5.0.7, and OTP 29.1.1, corresponding to asn1 from 3.0 before 5.3.4.3, 5.4.3.1, and 5.5.2. Whether OTP before OTP 17.0, corresponding to asn1 before 3.0, is affected is unknown.

Quoted source text, attributed separately from HOL analysis.

Related CVEs

  • Symfony: Exponential and Quadratic Parse Times in the YAML Parser Let a Single Document Hold a ProcessAlso CWE-407

Record context

Vulnerability class
Missing Auth
EPSS
Not reported
CWE IDs
CWE-407
Source
CVE List V5
Source checked
Nov 6, 2026
References
5 linked sources
Open source record