{"affected":[{"ranges":[{"events":[{"introduced":"84adefa331c4159d432d22840663c38f155cd4c1"},{"fixed":"0fe2c02fdc06fab1c63be9db1a7456993d20f838"}],"repo":"https://github.com/erlang/otp","type":"GIT"}]}],"aliases":["GHSA-qghx-23m5-r55m","CVE-2026-65634"],"credits":[{"name":"tynus2","type":"REPORTER"},{"name":"Lukas Backström","type":"REPORTER"},{"name":"John Högberg","type":"REMEDIATION_DEVELOPER"}],"database_specific":{"capec_ids":["CAPEC-229"],"cpe_ids":["cpe:2.3:a:erlang:erlang\\/otp:*:*:*:*:*:*:*:*"],"cwe_ids":["CWE-407"]},"details":"## Summary\n\nInefficient 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.\n\nThe 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.\n\nThe 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).\n\nThis 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`.\n\nThis 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.","id":"EEF-CVE-2026-65634","modified":"2026-09-22T08:49:25.580433Z","published":"2026-09-22T08:49:24.743Z","references":[{"type":"ADVISORY","url":"https://github.com/erlang/otp/security/advisories/GHSA-qghx-23m5-r55m"},{"type":"WEB","url":"https://cna.erlef.org/cves/CVE-2026-65634.html"},{"type":"WEB","url":"https://www.erlang.org/doc/system/versions.html#order-of-versions"},{"type":"FIX","url":"https://github.com/erlang/otp/commit/0fe2c02fdc06fab1c63be9db1a7456993d20f838"}],"related":[],"schema_version":"1.7.3","severity":[{"score":"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","type":"CVSS_V4"}],"summary":"Superlinear CPU denial of service in Erlang/OTP ASN.1 OBJECT IDENTIFIER decoder","upstream":[]}