CVE catalog

CVE-2019-18840

wolfssl affected and fixed versions

In wolfSSL 4.1.0 through 4.2.0c, there are missing sanity checks of memory accesses in parsing ASN.1 certificate data while handshaking. Specifically, there is a one-byte heap-based buffer overflow inside the DecodedCert structure in GetName in wolfcrypt/src/asn.c because the domain name location index is mishandled. Because a pointer is overwritten, there is an invalid free.

Severity: Medium
Published: Nov 9, 2019, 1:15:00 PM UTC
Source: [NVD] · [CVE record]
EPSS: 1.97% · Oct 27, 2026

Projects and upstream resources

[wolfssl][Source-reported homepage]

Reported versions and fixes

Each observation applies to its named package, distribution, and release. Distribution backports can fix a vulnerability while retaining an older upstream version number.

Distribution / release	Package	Version	Status	Source
Debiantrixie	wolfssl	`4.2.0+dfsg-3`	FixedDistribution-reported fixed boundary	[CVE-2019-18840]
Debiantrixie	wolfssl	`5.7.2-0.1+deb13u2`	Fixed	[CVE-2019-18840]
Debiansid	wolfssl	`4.2.0+dfsg-3`	FixedDistribution-reported fixed boundary	[CVE-2019-18840]
Debiansid	wolfssl	`5.9.2-1.2`	Fixed	[CVE-2019-18840]
Debianbookworm-security	wolfssl	`5.5.4-2+deb12u3`	Fixed	[CVE-2019-18840]
Debianbookworm	wolfssl	`4.2.0+dfsg-3`	FixedDistribution-reported fixed boundary	[CVE-2019-18840]
Debianbookworm	wolfssl	`5.5.4-2+deb12u2`	Fixed	[CVE-2019-18840]
Ubuntu20.04	wolfssl	`4.2.0+dfsg-3`	Fixed	[UBUNTU-CVE-2019-18840]Apr 22, 2026, 12:14:39 PM UTC

Showing 8 fix observations. All 11 observations, including unknown and conflicting reports, are available below.

Provider details and historical evidence

Distribution / release	Package	Version	Status	Source
Debianbookworm	wolfssl	`4.2.0+dfsg-3`	FixedDistribution-reported fixed boundary	[CVE-2019-18840]
Debianbookworm	wolfssl	`5.5.4-2+deb12u2`	Fixed	[CVE-2019-18840]
Debianbookworm-security	wolfssl	`5.5.4-2+deb12u3`	Fixed	[CVE-2019-18840]
Debiansid	wolfssl	`4.2.0+dfsg-3`	FixedDistribution-reported fixed boundary	[CVE-2019-18840]
Debiansid	wolfssl	`5.9.2-1.2`	Fixed	[CVE-2019-18840]
Debiantrixie	wolfssl	`4.2.0+dfsg-3`	FixedDistribution-reported fixed boundary	[CVE-2019-18840]
Debiantrixie	wolfssl	`5.7.2-0.1+deb13u2`	Fixed	[CVE-2019-18840]
Ubuntu20.04	wolfssl	`4.1.0+dfsg-2`	Affected	[UBUNTU-CVE-2019-18840]Apr 22, 2026, 12:14:39 PM UTC
Ubuntu20.04	wolfssl	`4.2.0+dfsg-1`	Affected	[UBUNTU-CVE-2019-18840]Apr 22, 2026, 12:14:39 PM UTC
Ubuntu20.04	wolfssl	`4.2.0+dfsg-2`	Affected	[UBUNTU-CVE-2019-18840]Apr 22, 2026, 12:14:39 PM UTC
Ubuntu20.04	wolfssl	`4.2.0+dfsg-3`	Fixed	[UBUNTU-CVE-2019-18840]Apr 22, 2026, 12:14:39 PM UTC

Original provider fields

{
  "package_releases": [
    {
      "name": "wolfssl",
      "status": "fixed",
      "release": "sid",
      "version": "5.9.2-1.2"
    },
    {
      "name": "wolfssl",
      "status": "fixed",
      "release": "trixie",
      "version": "5.7.2-0.1+deb13u2"
    },
    {
      "name": "wolfssl",
      "status": "fixed",
      "release": "bookworm",
      "version": "5.5.4-2+deb12u2"
    },
    {
      "name": "wolfssl",
      "status": "fixed",
      "release": "bookworm-security",
      "version": "5.5.4-2+deb12u3"
    }
  ],
  "fixed_versions": [
    {
      "bug": null,
      "name": "wolfssl",
      "type": "source",
      "origin": null,
      "release": "sid",
      "urgency": "not yet assigned",
      "fixed_version": "4.2.0+dfsg-3"
    },
    {
      "bug": null,
      "name": "wolfssl",
      "type": "source",
      "origin": null,
      "release": "trixie",
      "urgency": "not yet assigned",
      "fixed_version": "4.2.0+dfsg-3"
    },
    {
      "bug": null,
      "name": "wolfssl",
      "type": "source",
      "origin": null,
      "release": "bookworm",
      "urgency": "not yet assigned",
      "fixed_version": "4.2.0+dfsg-3"
    }
  ],
  "distribution_packages": [
    {
      "name": "wolfssl",
      "distro": "ubuntu",
      "ranges": [
        {
          "type": "ECOSYSTEM",
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "4.2.0+dfsg-3"
            }
          ]
        }
      ],
      "release": "20.04",
      "versions": [
        "4.1.0+dfsg-2",
        "4.2.0+dfsg-1",
        "4.2.0+dfsg-2"
      ],
      "ecosystem": "deb",
      "provider_url": "https://osv.dev/vulnerability/UBUNTU-CVE-2019-18840",
      "fixed_version": "4.2.0+dfsg-3",
      "provider_source": "pypi",
      "provider_record_id": "UBUNTU-CVE-2019-18840",
      "provider_updated_at": "2026-04-22T12:14:39.369581Z"
    }
  ]
}

OpenFactory catalog packages

Matching against OpenFactory catalog package versions is in progress.

[Debian 12 (Bookworm)]

[libwolfssl35]Unknown
Source package: [wolfssl]
Details (4)
- 5.5.4-2+deb12u2 · amd64 · bookworm
  Fixed · Fixed: 4.2.0+dfsg-3
  dsa · wolfssl · debian · bookworm; dsa · wolfssl · debian · 12
- 5.5.4-2+deb12u2 · arm64 · bookworm
  Fixed · Fixed: 4.2.0+dfsg-3
  dsa · wolfssl · debian · bookworm; dsa · wolfssl · debian · 12
- 5.5.4-2+deb12u3 · amd64 · bookworm-security
  Fixed · Fixed: 4.2.0+dfsg-3
  dsa · wolfssl · debian · bookworm; dsa · wolfssl · debian · 12
- 5.5.4-2+deb12u3 · arm64 · bookworm-security
  Fixed · Fixed: 4.2.0+dfsg-3
  dsa · wolfssl · debian · bookworm; dsa · wolfssl · debian · 12
[libwolfssl-dev]Unknown
Source package: [wolfssl]
Details (4)
- 5.5.4-2+deb12u2 · amd64 · bookworm
  Fixed · Fixed: 4.2.0+dfsg-3
  dsa · wolfssl · debian · bookworm; dsa · wolfssl · debian · 12
- 5.5.4-2+deb12u2 · arm64 · bookworm
  Fixed · Fixed: 4.2.0+dfsg-3
  dsa · wolfssl · debian · bookworm; dsa · wolfssl · debian · 12
- 5.5.4-2+deb12u3 · amd64 · bookworm-security
  Fixed · Fixed: 4.2.0+dfsg-3
  dsa · wolfssl · debian · bookworm; dsa · wolfssl · debian · 12
- 5.5.4-2+deb12u3 · arm64 · bookworm-security
  Fixed · Fixed: 4.2.0+dfsg-3
  dsa · wolfssl · debian · bookworm; dsa · wolfssl · debian · 12

[Debian 13 (Trixie)]

[libwolfssl42t64]Unknown
Source package: [wolfssl]
Details (2)
- 5.7.2-0.1+deb13u1 · amd64 · trixie
  Fixed · Fixed: 4.2.0+dfsg-3
  dsa · wolfssl · debian · 13
- 5.7.2-0.1+deb13u1 · arm64 · trixie
  Fixed · Fixed: 4.2.0+dfsg-3
  dsa · wolfssl · debian · 13
[libwolfssl-dev]Unknown
Source package: [wolfssl]
Details (2)
- 5.7.2-0.1+deb13u1 · amd64 · trixie
  Fixed · Fixed: 4.2.0+dfsg-3
  dsa · wolfssl · debian · 13
- 5.7.2-0.1+deb13u1 · arm64 · trixie
  Fixed · Fixed: 4.2.0+dfsg-3
  dsa · wolfssl · debian · 13

Observed: Oct 23, 2026, 5:42:11 PM UTC

References

[Debian Security Tracker] · [FIRST EPSS] · [OSV Package Vulnerability Database]