OTP vulnerability

What happened

Improper Validation of Specified Quantity in Input vulnerability in Erlang/OTP eldap allows a malicious or compromised LDAP server to degrade availability by returning a referral URL whose port component is a very long run of digits. eldap:parse_port/2 passes the port substring straight to list_to_integer/1 with no length bound. The surrounding try ... catch only rejects a value that fails to parse, so a syntactically valid port of up to roughly 1.26 million digits converts successfully and costs the caller hundreds of milliseconds of arbitrary-precision arithmetic per referral. The conversion function itself is documented to accept integers of any size, so bounding the input is the caller's responsibility. Reaching the flaw requires the application to pass a server-supplied referral to eldap:parse_ldap_url/1, which eldap never calls itself: referral strings are returned to the caller unparsed. This issue affects OTP from OTP 17.0 before OTP 27.3.4.17, from OTP 28.0 before OTP 28.5.0.6, and from OTP 29.0 before OTP 29.0.6, corresponding to eldap from 1.0.3 before 1.2.14.2, from 1.2.15 before 1.2.16.1, and from 1.3 before 1.3.1.

Affected versions

OTP: 17.0 through before 27.3.4.17 (otp); 28.0 through before 28.5.0.6 (otp); 29.0 through before 29.0.6 (otp); 1.0.3 through before 1.2.14.2 (otp); 1.2.15 through before 1.2.16.1 (otp); 1.3 through before 1.3.1 (otp); d8dbf15de4fa1a08b9a05e7d8e08fdb025fe1dc3 through before * (git) Fixed: See vendor advisory.

Why it matters

Review the vendor advisory and exposure of the affected product to determine operational impact.

Detection & mitigation

• Apply vendor-provided updates or mitigations.
• Review affected product exposure and access logs.