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Vulnerability · Published Mar 15, 2022 · Assigned by openssl

CVE-2022-0778Infinite loop in BN_mod_sqrt() reachable when parsing certificates

High 7.5

In plain English

A high-severity infinite loop in OpenSSL from OpenSSL. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 73.2% (higher than 99.5% of all known vulnerabilities). Ready-made attack tooling exists: public proof-of-concept code. Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)7.5High
Exploit odds (30 days)73.2%top 0.5% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack tooling1Public PoC

Official description

The BN_mod_sqrt() function, which computes a modular square root, contains a bug that can cause it to loop forever for non-prime moduli. Internally this function is used when parsing certificates that contain elliptic curve public keys in compressed form or explicit elliptic curve parameters with a base point encoded in compressed form. It is possible to trigger the infinite loop by crafting a certificate that has invalid explicit curve parameters. Since certificate parsing happens prior to verification of the certificate signature, any process that parses an externally supplied certificate may thus be subject to a denial of service attack. The infinite loop can also be reached when parsing crafted private keys as they can contain explicit elliptic curve parameters. Thus vulnerable situations include: - TLS clients consuming server certificates - TLS servers consuming client certificates - Hosting providers taking certificates or private keys from customers - Certificate authorities parsing certification requests from subscribers - Anything else which parses ASN.1 elliptic curve parameters Also any other applications that use the BN_mod_sqrt() where the attacker can control the parameter values are vulnerable to this DoS issue. In the OpenSSL 1.0.2 version the public key is not parsed during initial parsing of the certificate which makes it slightly harder to trigger the infinite loop. However any operation which requires the public key from the certificate will trigger the infinite loop. In particular the attacker can use a self-signed certificate to trigger the loop during verification of the certificate signature. This issue affects OpenSSL versions 1.0.2, 1.1.1 and 3.0. It was addressed in the releases of 1.1.1n and 3.0.2 on the 15th March 2022. Fixed in OpenSSL 3.0.2 (Affected 3.0.0,3.0.1). Fixed in OpenSSL 1.1.1n (Affected 1.1.1-1.1.1m). Fixed in OpenSSL 1.0.2zd (Affected 1.0.2-1.0.2zc).

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
AlmaLinux:8compat-openssl101:1.0.2o-4.el8_6ALSA-2022:5326
AlmaLinux:8openssl1:1.1.1k-6.el8_5ALSA-2022:1065
AlmaLinux:8openssl-devel1:1.1.1k-6.el8_5ALSA-2022:1065
AlmaLinux:8openssl-libs1:1.1.1k-6.el8_5ALSA-2022:1065
AlmaLinux:8openssl-perl1:1.1.1k-6.el8_5ALSA-2022:1065
Alpine:v3.20libressl3.4.3-r0ALPINE-CVE-2022-0778
Alpine:v3.21libressl3.4.3-r0ALPINE-CVE-2022-0778
Alpine:v3.22libressl3.4.3-r0ALPINE-CVE-2022-0778
Alpine:v3.23libressl3.4.3-r0ALPINE-CVE-2022-0778
Alpine:v3.24libressl3.4.3-r0ALPINE-CVE-2022-0778
Alpine:v3.20libretls3.5.1-r0ALPINE-CVE-2022-0778
Alpine:v3.21libretls3.5.1-r0ALPINE-CVE-2022-0778
Alpine:v3.22libretls3.5.1-r0ALPINE-CVE-2022-0778
Alpine:v3.23libretls3.5.1-r0ALPINE-CVE-2022-0778
Alpine:v3.24libretls3.5.1-r0ALPINE-CVE-2022-0778
Alpine:v3.20lighthouse2.2.0-r0ALPINE-CVE-2022-0778
Alpine:v3.21lighthouse2.2.0-r0ALPINE-CVE-2022-0778
Alpine:v3.22lighthouse2.2.0-r0ALPINE-CVE-2022-0778
Alpine:v3.23lighthouse2.2.0-r0ALPINE-CVE-2022-0778
Alpine:v3.24lighthouse2.2.0-r0ALPINE-CVE-2022-0778
Alpine:v3.20openjdk1111.0.15_p10-r0ALPINE-CVE-2022-0778
Alpine:v3.21openjdk1111.0.15_p10-r0ALPINE-CVE-2022-0778
Alpine:v3.22openjdk1111.0.15_p10-r0ALPINE-CVE-2022-0778
Alpine:v3.23openjdk1111.0.15_p10-r0ALPINE-CVE-2022-0778
Alpine:v3.24openjdk1111.0.15_p10-r0ALPINE-CVE-2022-0778
Alpine:v3.20openssl3.0.2-r0ALPINE-CVE-2022-0778
Alpine:v3.21openssl3.0.2-r0ALPINE-CVE-2022-0778
Alpine:v3.22openssl3.0.2-r0ALPINE-CVE-2022-0778
Alpine:v3.23openssl3.0.2-r0ALPINE-CVE-2022-0778
Alpine:v3.24openssl3.0.2-r0ALPINE-CVE-2022-0778
Debian:12openssl1.1.1n-1DEBIAN-CVE-2022-0778
Debian:13openssl1.1.1n-1DEBIAN-CVE-2022-0778
Debian:14openssl1.1.1n-1DEBIAN-CVE-2022-0778
Rocky Linux:8compat-openssl101:1.0.2o-4.el8_6RLSA-2022:5326
Rocky Linux:9compat-openssl111:1.1.1k-4.el9_0RLSA-2022:4899
Rocky Linux:8openssl1:1.1.1k-6.el8_5RLSA-2022:1065
Ubuntu:22.04:LTSedk22022.02-3ubuntu0.22.04.4UBUNTU-CVE-2022-0778
Ubuntu:22.04:LTSedk22022.02-3ubuntu0.22.04.4USN-7894-1
Ubuntu:24.04:LTSedk22024.02-2ubuntu0.6USN-7894-1
Ubuntu:22.04:LTSnodejs12.22.9~dfsg-1ubuntu3.1USN-6457-1
Ubuntu:22.04:LTSnodejs12.22.9~dfsg-1ubuntu3.1UBUNTU-CVE-2022-0778
Ubuntu:22.04:LTSopenssl3.0.2-0ubuntu1UBUNTU-CVE-2022-0778

Affected products (as reported)

VendorProductVersions
OpenSSL OpenSSL Fixed in OpenSSL 3.0.2 (Affected 3.0.0,3.0.1)Fixed in OpenSSL 1.1.1n (Affected 1.1.1-1.1.1m)Fixed in OpenSSL 1.0.2zd (Affected 1.0.2-1.0.2zc)

Weakness: CWE-835 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References