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HIGH

CVE-2019-3823

CVSS v3

7.5

HIGH

EPSS Score

4.1 %

exploit probability, as of 2026-10-20

CISA KEV

No

known exploited

Exploitation

—

SSVC status

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Affected and fixed versions

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Vendor advisories

  • CVE-2019-3823 Red Hat Product Security46 products fixed · 14 known affected

    curl: SMTP end-of-response out-of-bounds read

    rh-dotnetcore10-curl.src as a component of .NET Core 1.0 on Red Hat Enterprise Linux · rh-dotnetcore11-curl.src as a component of .NET Core 1.1 on Red Hat Enterprise Linux · rh-dotnet21-curl.src as a component of .NET Core 2.1 on Red Hat Enterprise Linux

  • SSA-936080 Siemens ProductCERT3 known affected

    SSA-936080: Multiple Vulnerabilities in Third-Party Component libcurl

    SCALANCE SC600 Family · SIMATIC CM 1542-1 · SIMATIC CP 343-1 Advanced (incl. SIPLUS variants)

  • RHSA-2019:3701 Red Hat Product Security45 products fixed

    Red Hat Security Advisory: curl security and bug fix update

  • RHSA-2019:1543 Red Hat Product Security1 product fixed

    Red Hat Security Advisory: Red Hat JBoss Core Services Apache HTTP Server 2.4.29 SP2 security update

  • ICSA-19-099-04 CISA2 known affected

    Siemens SINEMA Remote Connect (Update A)

    SINEMA Remote Connect Client: All versions < V2.0 HF1 · SINEMA Remote Connect Server: All versions < V2.0

  • ICSA-21-068-10 CISA1 known affected

    Siemens SCALANCE and SIMATIC libcurl (Update B)

    Siemens SINEMA Remote Connect Client: All versions < V2.0 HF1

Full record on NVD

Description

libcurl versions from 7.34.0 to before 7.64.0 are vulnerable to a heap out-of-bounds read in the code handling the end-of-response for SMTP. If the buffer passed to `smtp_endofresp()` isn't NUL terminated and contains no character ending the parsed number, and `len` is set to 5, then the `strtol()` call reads beyond the allocated buffer. The read contents will not be returned to the caller.

Technical details

Published
2019-02-06

Frequently asked questions

What is CVE-2019-3823?

libcurl versions from 7.34.0 to before 7.64.0 are vulnerable to a heap out-of-bounds read in the code handling the end-of-response for SMTP. If the buffer passed to `smtp_endofresp()` isn't NUL terminated and contains no character ending the parsed number, and `len` is set to 5, then the `strtol()` call reads beyond the allocated buffer. The read contents will not be returned to the caller.

Is CVE-2019-3823 actively exploited?

Active exploitation of CVE-2019-3823 has not been confirmed. Its EPSS score was 4.1% on 2026-10-20, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2019-3823?

CVE-2019-3823 has a CVSS v3 base score of 7.5 (HIGH severity).

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