CVE-2026-54872

Description

Issue summary: The generic elliptic-curve scalar multiplication used for ECDSA and SM2 signature operations with curves that do not have a dedicated implementation leaks information about the secret nonce through timing. Impact summary: An attacker able to measure signing times may learn information about the per-signature secret nonce, which over many signatures can, via a lattice / Hidden Number Problem attack, lead to recovery of the private key. CWE: CWE-208: Observable Timing Discrepancy Description: The generic elliptic-curve scalar multiplication used for curves that do not have a dedicated constant-time implementation pads the secret scalar with non-constant-time BIGNUM operations, so the time taken depends on the value of the secret scalar derived from the ECDSA and SM2 nonce. The leak is very small; observing it requires a large number of measurements. The effect is largest for curves whose group order lies on a machine-word boundary, such as brainpoolP384r1. Applications using ECDSA signing over the Brainpool and other generic prime curves, and SM2 signing on platforms that use the generic implementation, are vulnerable to this issue. The NIST curves P-256, P-384 and P-521 use dedicated constant-time implementations and are not affected. FIPS Impact: no The FIPS modules are not affected: the approved NIST curves used in the FIPS provider have dedicated constant-time implementations and do not use the affected code path.

Read the notes from the security team

Why is this CVE low priority?

OpenSSL developers have rated this issue as being low severity

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Status

Show unmaintained releases

Package	Ubuntu Release	Status
openssl	26.04 LTS resolute	Fixed 3.5.5-1ubuntu3.6
	24.04 LTS noble	Fixed 3.0.13-0ubuntu3.16
	22.04 LTS jammy	Fixed 3.0.2-0ubuntu1.30
	20.04 LTS focal	Fixed 1.1.1f-1ubuntu2.24+esm6
	18.04 LTS bionic	Fixed 1.1.1-1ubuntu2.1~18.04.23+esm11
	16.04 LTS xenial	Fixed 1.0.2g-1ubuntu4.20+esm19
	14.04 LTS trusty	Fixed 1.0.1f-1ubuntu2.27+esm17
openssl-fips	26.04 LTS resolute	Not in release
	24.04 LTS noble	Not in release
	22.04 LTS jammy	Not in release
openssl1.0	26.04 LTS resolute	Not in release
	24.04 LTS noble	Not in release
	22.04 LTS jammy	Not in release
	18.04 LTS bionic	Fixed 1.0.2n-1ubuntu5.13+esm7
nodejs	26.04 LTS resolute	Not affected
	24.04 LTS noble	Not affected
	22.04 LTS jammy	Vulnerable
	20.04 LTS focal	Not affected
	18.04 LTS bionic	Needs evaluation
	16.04 LTS xenial	Needs evaluation
	14.04 LTS trusty	Not affected
edk2	26.04 LTS resolute	Needs evaluation
	24.04 LTS noble	Needs evaluation
	22.04 LTS jammy	Needs evaluation
	20.04 LTS focal	Needs evaluation
	18.04 LTS bionic	Needs evaluation
	16.04 LTS xenial	Needs evaluation
edk2-hwe	26.04 LTS resolute	Needs evaluation
	24.04 LTS noble	Not in release
	22.04 LTS jammy	Not in release

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Notes

mdeslaur

edk2 in jammy embeds OpenSSL 1.1.1j edk2 in noble embeds OpenSSL 3.0.9 edk2 in resolute embeds OpenSSL 3.5.1 edk2 in stonking embeds OpenSSL 3.5.1 nodejs in jammy embeds OpenSSL 1.1.1m 4.0, 3.6, 3.5, 3.4, 3.0, 1.1.1 and 1.0.2 are vulnerable

Severity score breakdown

CVSS version: CVSS v3.0

Base score 3.7 · Low

Base metrics

Parameter	Value
Attack vector	Network
Attack complexity	High
Privileges required	None
User interaction	None
Scope	Unchanged
Confidentiality impact	Low
Integrity impact	None
Availability impact	None

Scores

Parameter	Value
Base score	3.7 · Low
Exploitability score	-
Impact score	-

Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N

References

Related Ubuntu Security Notices (USN)

USN-8847-1
OpenSSL vulnerabilities
29 September 2026

USN-8847-2
OpenSSL vulnerabilities
29 September 2026