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CVE Record

CVE-2019-19977: libESMTP through 1.0.6 mishandles domain copying into a fixed-size buffer in ntlm_build_type_2 in ntlm/ntlm...

libESMTP through 1.0.6 mishandles domain copying into a fixed-size buffer in ntlm_build_type_2 in ntlm/ntlmstruct.c, as demonstrated by a stack-based buffer over-read.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

This CVE affects libESMTP through 1.0.6, a mail-sending library. A flaw in NTLM authentication handling copies a domain value into a fixed-size stack buffer incorrectly, causing a stack buffer over-read. The public bundle does not provide a CVSS score, confirmed exploit activity, or vendor-fixed version.

Executive priority

Treat this as a targeted dependency exposure issue, not a confirmed emergency. Prioritize discovery in mail-related systems and apply vendor guidance where available, especially if NTLM authentication is used. Business urgency is constrained by missing severity, exploit, and fix details.

Technical view

In ntlm/ntlmstruct.c, ntlm_build_type_2 mishandles domain copying into a fixed-size buffer. The CVE description says this was demonstrated as a stack-based buffer over-read. Evidence identifies libESMTP through 1.0.6, but the bundle does not specify CWE, patch commit, impact beyond over-read, or exploit reliability.

Likely exposure

Exposure is most likely where software links libESMTP through 1.0.6 and enables or reaches NTLM authentication handling. The bundle does not identify specific downstream products, package names, platforms, or internet-facing services.

Exploitation context

The source bundle does not show CISA KEV listing or any cited evidence of active exploitation. A public vulnerability write-up exists, but the provided facts only support a demonstrated over-read, not weaponized exploitation or broad abuse.

Researcher notes

The evidence is narrow: CVE metadata, a public write-up, an archived project page, and referenced source lines. Do not infer RCE, affected downstream products, or a fixed release from this bundle. Validation should focus on dependency presence, version, and NTLM code reachability.

Mitigation direction

  • Inventory applications and packages that include libESMTP through 1.0.6.
  • Check vendor or distribution advisories for patched libESMTP packages.
  • Reduce or disable NTLM authentication paths where operationally feasible.
  • Prioritize systems processing untrusted SMTP authentication exchanges.
  • Monitor for crashes or anomalies in mail-sending components using libESMTP.

Validation and detection

  • Confirm installed libESMTP version and whether it is 1.0.6 or earlier.
  • Identify binaries or services dynamically or statically linked to libESMTP.
  • Review whether NTLM support is enabled or reachable in affected workflows.
  • Compare local source packages against ntlm/ntlmstruct.c references.
  • Check security advisories from the operating system or package maintainer.
Prepared
Confidence
medium
Sources
5

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

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CVE-2019-19977 mapping review

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
0Timeline events
0ADP providers
4Source links

CVSS and timeline data

No CVSS vectors or timeline events were available in the normalized CVE source material.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
n/an/an/aListed
Weakness

CWE details

No CWE listed

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.