4.3

CVE-2020-9488: apache apache log4j Improper Certificate Validation

Modified
AliasesUBUNTU-CVE-2020-9488DEBIAN-CVE-2020-9488GHSA-vwqq-5vrc-xw9h
Published 27-04-2020Last modified 29-05-2026

Vulnerability summary

CVE-2020-9488 is a medium (CVSS 4.3) Improper Certificate Validation vulnerability in apache apache log4j. EPSS estimates a 8.22% chance of exploitation in the next 30 days, higher than 94.8% of scored vulnerabilities.

Priority
Routine

Not severe (CVSS 3.7, network access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?
CVSS score
4.3/10
010
Medium · v2.0 (NVD)
EPSS score
8.22%
0%100%
Low · +0.12 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 2
DLA-2852-1RHSA-2020:3817

Timeline

  1. 27-04-2020
    PublishedVulnerability first disclosed.
  2. 29-05-2026
    Last modifiedVulnerability information updated.

Description

Improper validation of certificate with host mismatch in Apache Log4j SMTP appender. This could allow an SMTPS connection to be intercepted by a man-in-the-middle attack which could leak any log messages sent through that appender. Fixed in Apache Log4j 2.12.3 and 2.13.1

CVSS metrics

6 scores · 5 sources · 2 versions

EPSS trend

Probability

8.22%

Chance of exploitation in the next 30 days

Percentile

95%

Versus all other CVEs

30-day change

Increase +0.12 pp

From 8.10% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: network-reachable, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.

Oracle43 products
Apache2 products
  • apache log4jlog4j-core 2.13.0 | ≥ log4j-core, < 2.12.3
  • log4j≥ 2.0, < 2.3.2 | ≥ 2.4, < 2.12.3 | ≥ 2.13.0, < 2.13.2
Debian2 products
Org.apache.logging.log4j2 products
  • log4j≥ 2.13.0, < 2.13.2 | ≥ 2.4.0, < 2.12.3 | < 2.3.2
  • log4j-core≥ 2.13.0, < 2.13.2 | ≥ 2.4.0, < 2.12.3 | < 2.3.2
Qos1 product
Ubuntu1 product
  • apache-log4j2All versions (No fix recorded) | < 2.16.0-0.20.04.1

6 vendors · 51 products

References

96 links
Show all 96 references