CVE-2026-34479

ADVISORY - github

Summary

The Log4j1XmlLayout from the Apache Log4j 1-to-Log4j 2 bridge fails to escape characters forbidden by the XML 1.0 standard, producing malformed XML output. Conforming XML parsers are required to reject documents containing such characters with a fatal error, which may cause downstream log processing systems to drop or fail to index affected records.

Two groups of users are affected:

Those using Log4j1XmlLayout directly in a Log4j Core 2 configuration file.
Those using the Log4j 1 configuration compatibility layer with org.apache.log4j.xml.XMLLayout specified as the layout class.

Users are advised to upgrade to Apache Log4j 1-to-Log4j 2 bridge version 2.25.4, which corrects this issue.

[!NOTE] The Apache Log4j 1-to-Log4j 2 bridge is deprecated and will not be present in Log4j 3. Users are encouraged to consult the Log4j 1 to Log4j 2 migration guide, and specifically the section on eliminating reliance on the bridge.

EPSS Score⁠: 0.00909 (0.589)

Common Weakness Enumeration (CWE)

ADVISORY - nist

CWE-116⁠

Improper Encoding or Escaping of Output

ADVISORY - github

CWE-116⁠

Improper Encoding or Escaping of Output

Impacted images

Advisories

NIST

CREATED

6 months ago

UPDATED

5 months ago

ADVISORY IDCVE-2026-34479⁠

EXPLOITABILITY SCORE

3.9

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)

CWE-116⁠

CVSS SCORE

6.9medium

GitHub

CREATED

6 months ago

UPDATED

6 months ago

ADVISORY IDGHSA-h383-gmxw-35v2⁠

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)

CWE-116⁠

CVSS SCORE

6.9medium

Debian

CREATED

6 months ago

UPDATED

23 days ago

ADVISORY IDCVE-2026-34479⁠

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

CVSS SCORE

N/Alow

Ubuntu

CREATED

6 months ago

UPDATED

5 months ago

ADVISORY IDCVE-2026-34479⁠

EXPLOITABILITY SCORE

3.9

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

CVSS SCORE

7.5medium

Chainguard

CREATED

1 month ago

UPDATED

1 month ago

ADVISORY ID

CGA-xv36-79hh-mj43

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

minimos

CREATED

6 months ago

UPDATED

6 months ago

ADVISORY ID

MINI-22x7-p6vf-g27p

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

minimos

CREATED

3 months ago

UPDATED

3 months ago

ADVISORY ID

MINI-287m-m9p4-r24r

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

minimos

CREATED

4 months ago

UPDATED

4 months ago

ADVISORY ID

MINI-2wjj-ghq4-f5hf

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

minimos

CREATED

5 months ago

UPDATED

5 months ago

ADVISORY ID

MINI-34j6-c8vq-8c95

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

minimos

CREATED

6 months ago

UPDATED

6 months ago

ADVISORY ID

MINI-35x4-5mwx-2r6x

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

minimos

CREATED

6 months ago

UPDATED

6 months ago

ADVISORY ID

MINI-3m82-833v-7wg9

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

minimos

CREATED

10 days ago

UPDATED

10 days ago

ADVISORY ID

MINI-3w2q-xr78-cxww

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

minimos

CREATED

5 months ago

UPDATED

5 months ago

ADVISORY ID

MINI-3xxq-9mcg-vfvf

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

minimos

CREATED

6 months ago

UPDATED

6 months ago

ADVISORY ID

MINI-44m7-m6fv-pc9q

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

minimos

CREATED

5 months ago

UPDATED

5 months ago

ADVISORY ID

MINI-524w-82ph-qq74

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

minimos

CREATED

4 months ago

UPDATED

4 months ago

ADVISORY ID

MINI-5xcm-cvv3-r9q5

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

minimos

CREATED

6 months ago

UPDATED

6 months ago

ADVISORY ID

MINI-69wm-5834-fgrj

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

minimos

CREATED

3 months ago

UPDATED

3 months ago

ADVISORY ID

MINI-6c4w-hrfp-58w4

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

minimos

CREATED

6 months ago

UPDATED

6 months ago

ADVISORY ID

MINI-6gg5-wmjx-4rx8

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

minimos

CREATED

5 months ago

UPDATED

5 months ago

ADVISORY ID

MINI-6hx5-xc42-gg23

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

minimos

CREATED

4 months ago

UPDATED

4 months ago

ADVISORY ID

MINI-7cv6-g56h-qcmf

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

minimos

CREATED

6 months ago

UPDATED

6 months ago

ADVISORY ID

MINI-7w24-wgpq-mg4j

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

minimos

CREATED

4 months ago

UPDATED

4 months ago

ADVISORY ID

MINI-8mrr-p5g3-vp88

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

minimos

CREATED

4 months ago

UPDATED

4 months ago

ADVISORY ID

MINI-8pw3-26m5-v8vj

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

minimos

CREATED

5 months ago

UPDATED

5 months ago

ADVISORY ID

MINI-8r4q-wqwx-gv68

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

minimos

CREATED

4 months ago

UPDATED

4 months ago

ADVISORY ID

MINI-933j-mhch-jh57

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

minimos

CREATED

6 months ago

UPDATED

6 months ago

ADVISORY ID

MINI-9392-jgff-9rh4

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

minimos

CREATED

6 months ago

UPDATED

6 months ago

ADVISORY ID

MINI-9c6x-jvxh-jwcv

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

minimos

CREATED

4 months ago

UPDATED

4 months ago

ADVISORY ID

MINI-9hq3-rxxr-g8jr

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

minimos

CREATED

6 months ago

UPDATED

6 months ago

ADVISORY ID

MINI-cfx8-3mg3-jvx3

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

minimos

CREATED

4 months ago

UPDATED

4 months ago

ADVISORY ID

MINI-cj25-w84h-9f6g

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

minimos

CREATED

6 months ago

UPDATED

6 months ago

ADVISORY ID

MINI-gcf3-86w5-7v2x

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

minimos

CREATED

5 months ago

UPDATED

5 months ago

ADVISORY ID

MINI-ggm8-9xcm-g485

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

minimos

CREATED

6 months ago

UPDATED

6 months ago

ADVISORY ID

MINI-h452-vjm7-2r5w

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

minimos

CREATED

4 months ago

UPDATED

4 months ago

ADVISORY ID

MINI-h74h-6jm2-q83v

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

minimos

CREATED

4 months ago

UPDATED

4 months ago

ADVISORY ID

MINI-hgf4-5fv4-63m7

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

minimos

CREATED

6 months ago

UPDATED

6 months ago

ADVISORY ID

MINI-hw79-m453-qqmj

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

minimos

CREATED

6 months ago

UPDATED

6 months ago

ADVISORY ID

MINI-j3vr-hwcr-x86q

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

minimos

CREATED

6 months ago

UPDATED

6 months ago

ADVISORY ID

MINI-j6hh-g2gf-72x3

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

minimos

CREATED

4 months ago

UPDATED

4 months ago

ADVISORY ID

MINI-j9g6-54pp-88f9

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

minimos

CREATED

5 months ago

UPDATED

5 months ago

ADVISORY ID

MINI-jfmc-6jmv-3fxf

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

minimos

CREATED

4 months ago

UPDATED

4 months ago

ADVISORY ID

MINI-jrg2-r4q8-6wfj

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

minimos

CREATED

4 days ago

UPDATED

4 days ago

ADVISORY ID

MINI-m5pv-56mj-x754

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

minimos

CREATED

6 months ago

UPDATED

6 months ago

ADVISORY ID

MINI-mmx9-952w-3f6f

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

minimos

CREATED

5 months ago

UPDATED

5 months ago

ADVISORY ID

MINI-p63m-wm6r-h6p3

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

minimos

CREATED

4 months ago

UPDATED

4 months ago

ADVISORY ID

MINI-p99h-9wpv-4444

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

minimos

CREATED

6 months ago

UPDATED

6 months ago

ADVISORY ID

MINI-pc5c-wj3g-cgvw

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

minimos

CREATED

6 months ago

UPDATED

6 months ago

ADVISORY ID

MINI-pcvw-rq5m-9gw2

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

minimos

CREATED

5 months ago

UPDATED

5 months ago

ADVISORY ID

MINI-pjp5-w7p2-79h2

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

minimos

CREATED

6 months ago

UPDATED

6 months ago

ADVISORY ID

MINI-q4vp-58w9-8fg7

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

minimos

CREATED

6 months ago

UPDATED

6 months ago

ADVISORY ID

MINI-qrp6-rp44-qx9p

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

minimos

CREATED

5 months ago

UPDATED

5 months ago

ADVISORY ID

MINI-rj98-7jg3-hm6q

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

minimos

CREATED

4 months ago

UPDATED

4 months ago

ADVISORY ID

MINI-rvff-2fxj-fg4w

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

minimos

CREATED

10 days ago

UPDATED

10 days ago

ADVISORY ID

MINI-rvqf-8fvc-fc82

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

minimos

CREATED

4 months ago

UPDATED

4 months ago

ADVISORY ID

MINI-v8rm-34f2-fc9v

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

minimos

CREATED

6 months ago

UPDATED

6 months ago

ADVISORY ID

MINI-xv5m-fjc9-wp7p

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY