CVE-2022-0778

HIGH LAB

OpenSSL 1.0.2-1.0.2zc, 1.1.1-1.1.1m, 3.0.0-3.0.1 - Denial of Service via BN_mod_sqrt Infinite Loop

Title source: llm
STIX 2.1

Exploitation Summary

EIP tracks 6 public exploits for CVE-2022-0778. PoCs published by drago-96, jkakavas, yywing.

AI-analyzed exploit summary This repository contains a working proof-of-concept for CVE-2022-0778, which exploits an infinite loop vulnerability in OpenSSL's BN_mod_sqrt() function. The exploit crafts a malicious X.509 certificate with non-prime curve parameters to trigger a DoS condition.

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).

Exploits (6)

nomisec WORKING POC 184 stars
by drago-96 · poc
https://github.com/drago-96/CVE-2022-0778

This repository contains a working proof-of-concept for CVE-2022-0778, which exploits an infinite loop vulnerability in OpenSSL's BN_mod_sqrt() function. The exploit crafts a malicious X.509 certificate with non-prime curve parameters to trigger a DoS condition.

Classification
Working Poc 100%
Attack Type
Dos
Complexity
Moderate
Reliability
Reliable
Target: OpenSSL (versions prior to the fix)
No auth needed
Prerequisites: Vulnerable version of OpenSSL · Ability to deliver a malicious certificate to the target
devstral-2 · analyzed Feb 16, 2026 Full analysis →
nomisec WORKING POC 11 stars
by jkakavas · poc
https://github.com/jkakavas/CVE-2022-0778-POC

This PoC exploits CVE-2022-0778 by injecting a crafted certificate during a TLS handshake to trigger a DoS in vulnerable OpenSSL servers. It overrides the `TLSConnection._clientKeyExchange` method to send a maliciously crafted certificate in response to a CertificateRequest.

Classification
Working Poc 95%
Attack Type
Dos
Complexity
Moderate
Reliability
Reliable
Target: OpenSSL (versions 1.0.2, 1.1.1, and 3.0)
No auth needed
Prerequisites: A vulnerable OpenSSL server · A crafted certificate file (`crafted.crt`)
devstral-2 · analyzed Feb 16, 2026 Full analysis →
nomisec WORKING POC 10 stars
by yywing · poc
https://github.com/yywing/cve-2022-0778

This repository contains a proof-of-concept exploit for CVE-2022-0778, a vulnerability in the Go TLS library related to certificate handling. The exploit demonstrates a malicious client sending a specially crafted certificate to a vulnerable server, potentially causing a denial-of-service or other impacts.

Classification
Working Poc 90%
Attack Type
Dos
Complexity
Moderate
Reliability
Reliable
Target: Go TLS library (versions affected by CVE-2022-0778)
No auth needed
Prerequisites: Vulnerable Go TLS library version · Network access to the target server
devstral-2 · analyzed Feb 16, 2026 Full analysis →
nomisec WRITEUP 2 stars
by 0xUhaw · poc
https://github.com/0xUhaw/CVE-2022-0778

This repository provides a description and credits for CVE-2022-0778, a vulnerability related to SSL certificates causing DoS (CPU 100% or reboot). It references external PoCs but does not contain exploit code itself.

Classification
Writeup 90%
Attack Type
Dos
Complexity
Moderate
Reliability
Theoretical
Target: OpenSSL (versions affected by CVE-2022-0778)
No auth needed
Prerequisites: A vulnerable OpenSSL version · Ability to send a malformed SSL certificate to the target
devstral-2 · analyzed Feb 16, 2026 Full analysis →
nomisec WRITEUP
by jeongjunsoo · poc
https://github.com/jeongjunsoo/CVE-2022-0778

This repository provides a detailed writeup and analysis of CVE-2022-0778, an infinite loop vulnerability in OpenSSL's BN_mod_sqrt() function, leading to a Denial of Service (DoS) condition. It includes pre-patch and post-patch code comparisons, environment setup instructions, and references.

Classification
Writeup 100%
Attack Type
Dos
Complexity
Moderate
Reliability
Reliable
Target: OpenSSL 1.0.2, 1.1.1, 3.0
No auth needed
Prerequisites: Unpatched OpenSSL version (1.0.2, 1.1.1, or 3.0) · Ability to send crafted HTTPS requests to the target
devstral-2 · analyzed Feb 16, 2026 Full analysis →
nomisec WRITEUP
by Trinadh465 · poc
https://github.com/Trinadh465/openssl-1.1.1g_CVE-2022-0778

The repository contains configuration files and documentation for OpenSSL, specifically targeting CVE-2022-0778. It includes build configurations, templates, and helper scripts but lacks actual exploit code or proof-of-concept implementation.

Classification
Writeup 90%
Attack Type
Other
Complexity
Moderate
Reliability
Theoretical
Target: OpenSSL 1.1.1g
No auth needed
Prerequisites: Access to OpenSSL build environment
devstral-2 · analyzed Feb 16, 2026 Full analysis →

References (34)

Core 34
Core References
Third Party Advisory vendor-advisory
https://www.debian.org/security/2022/dsa-5103
Mailing List, Third Party Advisory mailing-list
https://lists.debian.org/debian-lts-announce/2022/03/msg00023.html
Mailing List, Third Party Advisory mailing-list
https://lists.debian.org/debian-lts-announce/2022/03/msg00024.html
Mailing List, Third Party Advisory mailing-list
http://seclists.org/fulldisclosure/2022/May/33
Mailing List, Third Party Advisory mailing-list
http://seclists.org/fulldisclosure/2022/May/35
Mailing List, Third Party Advisory mailing-list
http://seclists.org/fulldisclosure/2022/May/38
Third Party Advisory vendor-advisory
https://security.gentoo.org/glsa/202210-02

Scores

CVSS v3 7.5
EPSS 0.0754
EPSS Percentile 92.0%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CISA SSVC

Vulnrichment
Exploitation none
Automatable yes
Technical Impact partial

Lab Environment

COMMUNITY
Community Lab
docker pull vulhub/openssl:1.1.1m-with-curl
+3 more repos

Details

CWE
CWE-835
Status published
Products (21)
crates.io/openssl-src 300.0.0 - 300.0.5crates.io
debian/debian_linux 9.0
debian/debian_linux 10.0
debian/debian_linux 11.0
fedoraproject/fedora 34
fedoraproject/fedora 36
mariadb/mariadb 10.2.0 - 10.2.42
netapp/500f_firmware
netapp/a250_firmware
netapp/cloud_volumes_ontap_mediator
... and 11 more
Published Mar 15, 2022
Tracked Since Feb 18, 2026