Vulnerability MediumRUSTSEC-2021-0055 · openssl-src
RUSTSEC-2021-0055: NULL pointer deref in signature_algorithms processing
Short answerA security vulnerability in the openssl-src crate: NULL pointer deref in signature_algorithms processing. Medium severity (CVSS 5.9). Fixed in 111.15.0: update to a fixed version.
| Crate | openssl-src |
|---|---|
| Type | Vulnerability (denial-of-service) |
| Affected versions | Before 111.15.0. |
| Fixed in | 111.15.0 |
| Severity | Medium, CVSS 5.9 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H |
| Published | 2021-05-01 |
| Last changed | 2024-12-16 |
| Also known as | BIT-node-2021-3449, BIT-node-min-2021-3449, CVE-2021-3449, GHSA-83mx-573x-5rw9 |
What to do
- See which version you have:
cargo tree -i openssl-src(it also shows which of your dependencies pulls it in). - Update within your version requirement:
cargo update -p openssl-src. If the fix is a newer major or minor than your requirement allows, raise it in Cargo.toml (for exampleopenssl-src = "111.15.0") or update the dependency that pulls it in. - Check again with
cargo audit, or paste your Cargo.lock into our Cargo.toml checker.
Details from the advisory
An OpenSSL TLS server may crash if sent a maliciously crafted renegotiation ClientHello message from a client. If a TLSv1.2 renegotiation ClientHello omits the signature_algorithms extension (where it was present in the initial ClientHello), but includes a signature_algorithms_cert extension then a NULL pointer dereference will result, leading to a crash and a denial of service attack.
A server is only vulnerable if it has TLSv1.2 and renegotiation enabled (which is the default configuration). OpenSSL TLS clients are not impacted by this issue.
References
- Package: crates.io/crates/openssl-src
- Advisory: rustsec.org/advisories/RUSTSEC-2021-0055.html
- Web: www.openssl.org/news/secadv/20210325.txt
From the RustSec Advisory Database (CC0-1.0) via the OSV export, downloaded Oct 24, 2026. Severity score computed from the published CVSS vector.
Other advisories for openssl-src
- Vulnerability HighRUSTSEC-2020-0015 · 2020-04-25Crash causing Denial of Service attack
- Vulnerability HighRUSTSEC-2021-0056 · 2021-05-01CA certificate check bypass with X509_V_FLAG_X509_STRICT
- Vulnerability HighRUSTSEC-2021-0057 · 2021-05-01Integer overflow in CipherUpdate
- Vulnerability MediumRUSTSEC-2021-0058 · 2021-05-01Null pointer deref in `X509_issuer_and_serial_hash()`
- Vulnerability CriticalRUSTSEC-2021-0097 · 2021-08-24SM2 Decryption Buffer Overflow
- Vulnerability HighRUSTSEC-2021-0098 · 2021-08-24Read buffer overruns processing ASN.1 strings
- VulnerabilityRUSTSEC-2021-0129 · 2021-12-14Invalid handling of `X509_verify_cert()` internal errors in libssl
- VulnerabilityRUSTSEC-2022-0014 · 2022-03-15Infinite loop in `BN_mod_sqrt()` reachable when parsing certificates
Up next
Same crateopenssl-src: security historyEvery advisory for this crate, and whether it is safe to use today.Read it next →Did this answer your question?