CVE catalog

CVE-2026-6291

Severity: Medium · CVSS 6
Published: Jun 25, 2026, 6:16:41 PM UTC
Source: [NVD] · [CVE record]
EPSS: 0.24% · Oct 27, 2026

Bleichenbacher padding oracle in PKCS#7 KTRI decryption. When decrypting PKCS#7 EnvelopedData using RSA PKCS#1 v1.5 key transport, wolfSSL returned distinguishable error codes depending on whether RSA padding validation failed versus whether the decrypted content was malformed. An attacker able to submit crafted EnvelopedData messages and observe error responses could use this as a padding oracle to incrementally recover the encrypted Content Encryption Key (CEK). The fix generates a deterministic pseudo-random fake CEK on padding failure (via HMAC-SHA256) and proceeds with decryption identically, using constant-time operations throughout, so that all failure paths produce the same error regardless of padding validity.

Vulnerable and fixed packages

Distribution-reported package versions and fixes. These do not depend on matching against the OpenFactory package catalog.

Distribution	Package	Release	Version	Status
Debian	wolfssl	sid	`5.9.2-1.2`	fixed
Debian	wolfssl	trixie	`5.7.2-0.1+deb13u2`	vulnerable
Debian	wolfssl	bookworm	`5.5.4-2+deb12u2`	vulnerable
Debian	wolfssl	bookworm-security	`5.5.4-2+deb12u3`	vulnerable
Cpe	wolfssl	Not reported	Not reported	vulnerable
Cpe	wolfssl	Not reported	`5.9.2`	fixed

Fixed-version evidence

Distribution	Package	Type	Release	Fixed version	Urgency	Origin	Bugs
Debian	wolfssl	source	sid	`5.9.2-1`	not yet assigned	Not reported	[1140765]
Debian	wolfssl	source	trixie	`(unfixed)`	not yet assigned	Not reported	[1140765]
Debian	wolfssl	source	bookworm	`(unfixed)`	end-of-life	Not reported	[1140765]
Cpe	wolfssl	cpe	Not reported	`5.9.2`	Not reported	Not reported	Not reported

[Debian bug #1140765]

Notes

[trixie] wolfssl: Can be fixed in point release

OpenFactory catalog packages

[Debian 12 (Bookworm)]

[libwolfssl35]Affected
Source package: [wolfssl]
Details (4)
- 5.5.4-2+deb12u2 · amd64 · bookworm
  Affected
  nvd · wolfssl · debian · bookworm; nvd · wolfssl · debian · 12
- 5.5.4-2+deb12u2 · arm64 · bookworm
  Affected
  nvd · wolfssl · debian · bookworm; nvd · wolfssl · debian · 12
- 5.5.4-2+deb12u3 · amd64 · bookworm-security
  Affected
  nvd · wolfssl · debian · bookworm; nvd · wolfssl · debian · 12
- 5.5.4-2+deb12u3 · arm64 · bookworm-security
  Affected
  nvd · wolfssl · debian · bookworm; nvd · wolfssl · debian · 12
[libwolfssl-dev]Affected
Source package: [wolfssl]
Details (4)
- 5.5.4-2+deb12u2 · amd64 · bookworm
  Affected
  nvd · wolfssl · debian · bookworm; nvd · wolfssl · debian · 12
- 5.5.4-2+deb12u2 · arm64 · bookworm
  Affected
  nvd · wolfssl · debian · bookworm; nvd · wolfssl · debian · 12
- 5.5.4-2+deb12u3 · amd64 · bookworm-security
  Affected
  nvd · wolfssl · debian · bookworm; nvd · wolfssl · debian · 12
- 5.5.4-2+deb12u3 · arm64 · bookworm-security
  Affected
  nvd · wolfssl · debian · bookworm; nvd · wolfssl · debian · 12

[Debian 13 (Trixie)]

[libwolfssl42t64]Affected
Source package: [wolfssl]
Details (2)
- 5.7.2-0.1+deb13u1 · amd64 · trixie
  Affected
  nvd · wolfssl · debian · 13
- 5.7.2-0.1+deb13u1 · arm64 · trixie
  Affected
  nvd · wolfssl · debian · 13
[libwolfssl-dev]Affected
Source package: [wolfssl]
Details (2)
- 5.7.2-0.1+deb13u1 · amd64 · trixie
  Affected
  nvd · wolfssl · debian · 13
- 5.7.2-0.1+deb13u1 · arm64 · trixie
  Affected
  nvd · wolfssl · debian · 13

Observed: Oct 23, 2026, 9:45:24 PM UTC

References

[Debian Security Tracker] · [FIRST EPSS] · [National Vulnerability Database (NVD)] · [OSV Package Vulnerability Database]