SB20261001103 - Ubuntu update for openssl
Published: October 1, 2026
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 4 vulnerabilities.
1) Allocation of Resources Without Limits or Throttling (CVE-ID: CVE-2026-35189)
CWE-ID: CWE-770 - Allocation of Resources Without Limits or Throttling
CVSSv4: 8.7 [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]
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to allocation of resources without limits or throttling in relative CRL distribution point processing when caching X.509 extensions from a crafted certificate. A remote attacker can send a crafted certificate to cause a denial of service.
Multiple concurrent connections can produce similarly large memory allocations.
2) Information Exposure Through Timing Discrepancy (CVE-ID: CVE-2026-54872)
CWE-ID: CWE-208 - Information Exposure Through Timing Discrepancy
CVSSv4: 8.2 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N]
The vulnerability allows a remote attacker to recover a private key.
The vulnerability exists due to an observable timing discrepancy in generic elliptic-curve scalar multiplication when performing ECDSA or SM2 signing with curves lacking dedicated implementations. A remote attacker can measure signing times across many signatures to recover a private key.
The timing signal is small and is most pronounced for curves whose group order lies on a machine-word boundary.
3) Information Exposure Through Timing Discrepancy (CVE-ID: CVE-2026-77696)
CWE-ID: CWE-208 - Information Exposure Through Timing Discrepancy
CVSSv4: 8.2 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N]
The vulnerability allows a remote attacker to recover a private key.
The vulnerability exists due to an observable timing discrepancy in SM2 signature generation when performing arithmetic on secret nonce and private-key values. A remote attacker can measure signing times across many signatures to recover a private key.
The issue affects SM2 signature generation on all platforms.
4) Out-of-bounds read (CVE-ID: CVE-2026-84782)
CWE-ID: CWE-125 - Out-of-bounds read
CVSSv4: 6.3 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:L/SC:N/SI:N/SA:N]
The vulnerability allows a remote attacker to disclose heap memory contents or cause a denial of service.
The vulnerability exists due to an out-of-bounds read in OpenSSL DTLS retransmission handling when retransmitting a suspended DTLS handshake message write. A remote attacker can cause a suspended handshake message to be retransmitted to disclose heap memory contents or cause a denial of service.
Only applications that use DTLS are affected.
Remediation
Install update from vendor's website.