RUSTSEC-2023-0006: X.400 address type confusion in X.509 `GeneralName`

What to do

1. See which version you have: cargo tree -i openssl-src (it also shows which of your dependencies pulls it in).
2. 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 example openssl-src = "300.0.12") or update the dependency that pulls it in.
3. Check again with cargo audit, or paste your Cargo.lock into our Cargo.toml checker.

Details from the advisory

There is a type confusion vulnerability relating to X.400 address processing inside an X.509 GeneralName. X.400 addresses were parsed as an ASN1_STRING but the public structure definition for GENERAL_NAME incorrectly specified the type of the x400Address field as ASN1_TYPE. This field is subsequently interpreted by the OpenSSL function GENERAL_NAME_cmp as an ASN1_TYPE rather than an ASN1_STRING.

When CRL checking is enabled (i.e. the application sets the X509_V_FLAG_CRL_CHECK flag), this vulnerability may allow an attacker to pass arbitrary pointers to a memcmp call, enabling them to read memory contents or enact a denial of service. In most cases, the attack requires the attacker to provide both the certificate chain and CRL, neither of which need to have a valid signature. If the attacker only controls one of these inputs, the other input must already contain an X.400 address as a CRL distribution point, which is uncommon. As such, this vulnerability is most likely to only affect applications which have implemented their own functionality for retrieving CRLs over a network.

References

• Package: crates.io/crates/openssl-src
• Advisory: rustsec.org/advisories/RUSTSEC-2023-0006.html
• Web: www.openssl.org/news/secadv/20230207.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 MediumRUSTSEC-2021-0055 · 2021-05-01NULL pointer deref in signature_algorithms processing
• 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

Full security history of openssl-src