UBUNTU-CVE-2026-93599

See a problem?
Please try reporting it to the source first.
Source
https://ubuntu.com/security/CVE-2026-93599
Import Source
https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-93599.json
JSON Data
https://api.osv.dev/v1/vulns/UBUNTU-CVE-2026-93599
Upstream
Published
2026-09-21T00:00:00Z
Modified
2026-09-21T21:40:59Z
Severity
  • 7.5 (High) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H CVSS Calculator
  • 8.7 (High) CVSS_V4 - CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N CVSS Calculator
  • Ubuntu - medium
Summary
[none]
Details

rustls-webpki through 0.103.12 (and 0.104.0-alpha releases before 0.104.0-alpha.7) contains a reachable panic in bit_string_flags() in src/der.rs. The input guard fails to reject a named-bit BIT STRING whose content is exactly [0x00] (zero padding bits and no data bytes), so raw_bits.len() - 1 underflows on the empty slice and the subsequent index operation panics (subtract-with-overflow in debug, index-out-of-bounds in release). The condition is reachable through the public API BorrowedCertRevocationList::from_der() when a CRL contains an issuingDistributionPoint extension with such an onlySomeReasons value. Exploitation requires an application that explicitly opts in to CRL revocation checking by passing RevocationOptions to verify_for_usage() and that parses CRL bytes obtained from a source the attacker can influence; the default rustls configuration, which does not use RevocationOptions, is unaffected. A crafted CRL causes a denial of service via the panic. Fixed in 0.103.13 and 0.104.0-alpha.7.

References

Affected packages

Ubuntu:24.04:LTS / rust-rustls-webpki

Package

Name
rust-rustls-webpki
Purl
pkg:deb/ubuntu/rust-rustls-webpki?arch=source&distro=noble

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected

Affected versions

0.*
0.101.4-4
0.101.7-2.1

Ecosystem specific 

{
    "binaries":  [
        {
            "binary_name":  "librust-rustls-webpki-dev",
            "binary_version":  "0.101.7-2.1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-93599.json"

Ubuntu:26.04:LTS / rust-rustls-webpki

Package

Name
rust-rustls-webpki
Purl
pkg:deb/ubuntu/rust-rustls-webpki?arch=source&distro=resolute

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected

Affected versions

0.*
0.102.8-5
0.103.7-1
0.103.7-1build1
0.103.9+ds-1
0.103.9+ds-2

Ecosystem specific 

{
    "binaries":  [
        {
            "binary_name":  "librust-rustls-webpki-dev",
            "binary_version":  "0.103.9+ds-2"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-93599.json"