CVE-2021-36386: n/a vulnerability

CVE-2021-36386: report_vbuild in report.c in Fetchmail before 6.4.20 sometimes omits initialization of the vsnprintf va_lis...

report_vbuild in report.c in Fetchmail before 6.4.20 sometimes omits initialization of the vsnprintf va_list argument, which might allow mail servers to cause a denial of service or possibly have unspecified other impact via long error messages. NOTE: it is unclear whether use of Fetchmail on any realistic platform results in an impact beyond an inconvenience to the client user.

UnknownCVSS not scoredNot KEV-listedUpdatedAug 4, 2024, 00:54 UTC (UTC+00:00)

Security readout for executives and security teams

Fetchmail versions before 6.4.20 can mishandle unusually long server error messages and may crash the client. The public record says realistic impact may be limited to inconvenience for the user, and no active exploitation is cited. Exposure is limited to systems running Fetchmail before 6.4.20, especially clients retrieving mail from untrusted or compromised mail servers. The source data does not identify broader affected products or server-side exposure. Treat this as routine patching unless Fetchmail is used with untrusted mail servers or failures disrupt critical workflows. Business risk appears low from the provided evidence, but affected clients should still be updated. Mitigation focus: Upgrade Fetchmail using vendor-supported packages.; Prefer 6.4.21 or later where available due to the 6.4.20 regression fix.; Apply relevant Fedora, Gentoo, or distribution security updates..

Prepared: Jun 2, 2026, 19:01 UTC (UTC+00:00)

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

Potential ATT&CK relevance

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Vulnerability profileCVE Program record

Severity: Unknown
CVSS: Not scored
Known Exploited: No
Published: Jul 29, 2021, 13:59 UTC (UTC+00:00)

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

6Source links

CVSS and timeline data

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

Source materials

CVE List V5 sourceCVE List V5
https://www.fetchmail.info/security.htmlCVE reference · x_refsource_MISC
https://www.fetchmail.info/fetchmail-SA-2021-01.txtCVE reference · x_refsource_CONFIRM
FEDORA-2021-47893f53edCVE reference · vendor-advisory, x_refsource_FEDORA
FEDORA-2021-b904d99ce5CVE reference · vendor-advisory, x_refsource_FEDORA
GLSA-202209-14CVE reference · vendor-advisory, x_refsource_GENTOO

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus

n/an/an/aListed

Weakness

CWE details

No CWE listed

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