DEBIAN-CVE-2026-42770

See a problem?
Please try reporting it to the source first.
Source
https://security-tracker.debian.org/tracker/CVE-2026-42770
Import Source
https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2026-42770.json
JSON Data
https://api.test.osv.dev/v1/vulns/DEBIAN-CVE-2026-42770
Upstream
Published
2026-06-09T17:17:08Z
Modified
2026-08-27T23:06:00Z
Severity
  • 3.7 (Low) CVSS_V3 - CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N CVSS Calculator
Summary
[none]
Details

Issue summary: When EVP_PKEY_derive_set_peer() is called with a DHX (X9.42) peer key, the peer key is not properly checked for the subgroup membership. Impact summary: A malicious peer which presents an X9.42 key carrying the victim's p and g parameters, a forged q = r (a small prime factor of the cofactor (p−1)/q_local), and a public value Y of order r can recover the victim's private key after a small number of key exchange attempts. When EVP_PKEY_derive_set_peer() is called with a DHX (X9.42) peer key, the subgroup membership check Y^q ≡ 1 (mod p) is performed using the peer's own q parameter, not the local key's q. The peer's domain parameters are then matched against the domain parameters of the private key, but the value of q is not compared. A malicious peer who presents an X9.42 key carrying the victim's p, g, a forged q = r (a small prime factor of the cofactor), and a public value Y of order r passes all checks. The shared secret then takes only r distinct values, leaking priv mod r. Repeating for each small-prime factor of the cofactor and combining via CRT recovers the full private key (Lim–Lee / small-subgroup-confinement attack). The realistic attack surface is narrow: principally CMP deployments with long-lived RA/CA DHX keys and bespoke enterprise or government applications using X9.42 DHX static keys with interactive protocols and therefore this issue was assigned Low severity. The FIPS modules in 4.0, 3.6, 3.5, 3.4, 3.1.2 and 3.0 are affected by this issue.

References

Affected packages

Debian:12 / openssl

Package

Name
openssl
Purl
pkg:deb/debian/openssl?arch=source&distro=bookworm

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected
Fixed
3.0.20-1~deb12u2

Affected versions

3.*
3.0.9-1
3.0.10-1~deb12u1
3.0.10-1
3.0.11-1~deb12u1
3.0.11-1~deb12u2
3.0.11-1
3.0.12-1
3.0.12-2
3.0.13-1~deb12u1
3.0.13-1~deb12u2
3.0.14-1~deb12u1
3.0.14-1~deb12u2
3.0.15-1~deb12u1
3.0.16-1~deb12u1
3.0.17-1~deb12u1
3.0.17-1~deb12u2
3.0.17-1~deb12u3
3.0.18-1~deb12u1
3.0.18-1~deb12u2
3.0.19-1~deb12u1
3.0.19-1~deb12u2
3.0.20-1~deb12u1

Ecosystem specific 

{
    "urgency":  "not yet assigned"
}

Database specific

source 
"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2026-42770.json"

Debian:13 / openssl

Package

Name
openssl
Purl
pkg:deb/debian/openssl?arch=source&distro=trixie

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected
Fixed
3.5.6-1~deb13u2

Affected versions

3.*
3.5.1-1
3.5.1-1+deb13u1
3.5.2-1
3.5.3-1
3.5.4-1~deb13u1
3.5.4-1~deb13u2
3.5.4-1
3.5.5-1~deb13u1
3.5.5-1~deb13u2
3.5.5-1
3.5.6-1~deb13u1

Ecosystem specific 

{
    "urgency":  "not yet assigned"
}

Database specific

source 
"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2026-42770.json"

Debian:14 / openssl

Package

Name
openssl
Purl
pkg:deb/debian/openssl?arch=source&distro=forky

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected
Fixed
3.6.3-1

Affected versions

3.*
3.5.1-1
3.5.2-1
3.5.3-1
3.5.4-1~deb13u1
3.5.4-1~deb13u2
3.5.4-1
3.5.5-1~deb13u1
3.5.5-1~deb13u2
3.5.5-1
3.5.6-1~deb13u1
3.5.6-1~deb13u2
3.5.7-1~deb13u1
3.5.7-1~deb13u2
3.6.0~~alpha1-1
3.6.0~~beta1-1
3.6.0-1
3.6.0-2
3.6.1-1
3.6.1-2
3.6.1-3
3.6.2-1

Ecosystem specific 

{
    "urgency":  "not yet assigned"
}

Database specific

source 
"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2026-42770.json"