Skip to content
Fencer Vulns
high 7.4

CVE-2020-15953 json

LibEtPan through 1.9.4, as used in MailCore 2 through 0.6.3 and other products, has a STARTTLS buffering issue that affects IMAP, SMTP, and…

published 2020-07-27 6 y ago modified 2026-06-17 4 mo ago also EUVD-2020-7924

cvss
7.4
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
2.4%
EPSS 2.4% chance of exploitation in 30 days, percentile 84%
public exploits
0
none known

Summary

LibEtPan through 1.9.4, as used in MailCore 2 through 0.6.3 and other products, has a STARTTLS buffering issue that affects IMAP, SMTP, and POP3. When a server sends a "begin TLS" response, the client reads additional data (e.g., from a meddler-in-the-middle attacker) and evaluates it in a TLS context, aka "response injection."

Patch / fix

  • libetpan Debian 14, Debian 13, Debian 12 1.9.4-3

debian advisories DEBIAN-CVE-2020-15953

  • libetpan Ubuntu 16.04 LTS 1.6-1ubuntu0.1

ubuntu advisories UBUNTU-CVE-2020-15953

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • libetpan Package Hub 15 SP2 1.9.4-bp152.4.3.1
  • libetpan openSUSE Leap 15.2 1.9.4-lp152.3.3.1

opensuse advisories openSUSE-SU-2020:1505-1openSUSE-SU-2020:1454-1

  • libetpan Alpine 3.24, Alpine 3.23, Alpine 3.22 +9 more 1.9.4-r1

alpine advisories ALPINE-CVE-2020-15953

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • libetpan Arch Linux 1.9.4-3

arch linux advisories AVG-1428

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2020-15953 updated cvss 7.4

libetpan: response injection via STARTTLS in IMAP

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

2.40% chance of exploitation in the next 30 days, higher than 84% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/dinhvh/libetpan/issues/386 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 7.4 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
NVD 2.0 5.8 AV:N/AC:M/Au:N/C:P/I:P/A:N

Classification

Weakness
  • CWE-74 Improper Neutralization of Special Elements in Output Used by a Downstream Component

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.