CVE-2026-65634

HIGHPre-NVD 8.28.2—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 8.2 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.4% (33rd percentile of EPSS-scored CVEs). GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
Trending — 3 sources updated this week
8.2EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.4%CVSS: 8.2Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

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.

CVSS v3
8.2
EG Score
8.2HIGHmedium confidence
EG Risk
52
EG Risk 52/100CISA SSVC

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity82% × 45%
Exploitation0% × 40%
Automatability100% × 15%
CISA SSVC: Track at low or medium mission impact; Attend at high (mission-essential systems).
Action: A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
EPSS PROB
0.4%
EPSS %ILE
33rd
KEV
Not listed

CISA SSVCTrack at low or medium mission impact; Attend at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.

Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

September 22, 2026

Last Modified

September 24, 2026

Advisory Details (5)

Auto-updated Sep 22, 2026
Patch available. Sources: github, github_commit.
github_commit

commit 0fe2c02fdc06 (erlang/otp)

Fix landed in erlang/otp commit 0fe2c02fdc06 — awaiting tagged release

https://github.com/erlang/otp/commit/0fe2c02fdc06fab1c63be9db1a7456993d20f838
generic

Versions — Erlang System Documentation v29.1

https://www.erlang.org/doc/system/versions.html#order-of-versions
generic

OSV - Open Source Vulnerabilities

https://osv.dev/vulnerability/EEF-CVE-2026-65634
generic

CVE-2026-65634

https://cna.erlef.org/cves/CVE-2026-65634.html
github Patch Available

Superlinear CPU Denial-of-Service in OID Decoder via Large Base-128 Arc · Advisory · erlang/otp · GitHub

https://github.com/erlang/otp/security/advisories/GHSA-qghx-23m5-r55m

Vendor Advisories for CVE-2026-65634(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 27× in last 7d / 49× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-10-04 01:35 UTCEG score recompute
  2. 2026-10-04 01:35 UTCVendor advisory
  3. 2026-10-03 14:26 UTCEPSS rescore
  4. 2026-10-03 13:57 UTCVendor advisory
  5. 2026-10-03 02:23 UTCEG score recompute
  6. 2026-10-03 02:23 UTCVendor advisory
  7. 2026-10-02 17:56 UTCEPSS rescore
  8. 2026-10-02 14:49 UTCVendor advisory
  9. 2026-10-02 03:19 UTCEG score recompute
  10. 2026-10-02 03:19 UTCVendor advisory
  11. 2026-10-01 19:50 UTCEPSS rescore
  12. 2026-10-01 15:48 UTCVendor advisory
  13. 2026-10-01 04:18 UTCVendor advisory
  14. 2026-09-30 16:48 UTCEG score recompute
  15. 2026-09-30 16:48 UTCVendor advisory
  16. 2026-09-30 15:03 UTCEPSS rescore
  17. 2026-09-30 04:19 UTCVendor advisory
  18. 2026-09-29 16:48 UTCEG score recompute
  19. 2026-09-29 16:48 UTCVendor advisory
  20. 2026-09-29 05:02 UTCEG score recompute
  21. 2026-09-29 05:02 UTCVendor advisory
  22. 2026-09-28 17:32 UTCEG score recompute
  23. 2026-09-28 17:32 UTCVendor advisory
  24. 2026-09-28 13:51 UTCEPSS rescore
  25. 2026-09-28 06:00 UTCVendor advisory
Show 24 more
  1. 2026-09-27 18:29 UTCEG score recompute
  2. 2026-09-27 18:29 UTCVendor advisory
  3. 2026-09-27 06:58 UTCVendor advisory
  4. 2026-09-26 19:27 UTCEG score recompute
  5. 2026-09-26 19:27 UTCVendor advisory
  6. 2026-09-26 15:59 UTCEPSS rescore
  7. 2026-09-26 07:57 UTCEG score recompute
  8. 2026-09-26 07:57 UTCVendor advisory
  9. 2026-09-25 20:23 UTCVendor advisory
  10. 2026-09-25 08:53 UTCVendor advisory
  11. 2026-09-24 21:23 UTCEG score recompute
  12. 2026-09-24 21:23 UTCVendor advisory
  13. 2026-09-24 20:27 UTCEG score recompute
  14. 2026-09-24 20:27 UTCVendor advisory
  15. 2026-09-24 17:14 UTCEG score recompute
  16. 2026-09-24 17:14 UTCVendor advisory
  17. 2026-09-23 18:13 UTCEG score recompute
  18. 2026-09-23 17:54 UTCEPSS rescore
  19. 2026-09-22 19:12 UTCEG score recompute
  20. 2026-09-22 11:35 UTCEG score recompute
  21. 2026-09-22 10:26 UTCEG score recompute
  22. 2026-09-22 09:34 UTCEG score recompute
  23. 2026-09-22 08:56 UTCEG score recompute
  24. 2026-09-22 08:55 UTCMITRE cvelistV5first tracked

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Frequently asked(5)

What is CVE-2026-65634?
CVE-2026-65634 is a high vulnerability published on September 22, 2026. 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 asn1rttber:decsubidentifiers/3 in lib/asn1/src/asn1rttber.erl and the…
When was CVE-2026-65634 disclosed?
CVE-2026-65634 was first published on September 22, 2026, with the most recent update on September 24, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-65634 actively exploited?
CVE-2026-65634 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.4% probability of exploitation in the next 30 days (33rd percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-65634?
CVE-2026-65634 has a CVSS base score of 8.2 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-65634?
A fix for CVE-2026-65634 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-65634 are linked in the Vendor Advisories panel on this page.

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