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CVE-2026-4539

pygments archetype.py AdlLexer redos

4.8 MediumFix available

A security flaw has been discovered in pygments up to 2.19.2. The impacted element is the function AdlLexer of the file pygments/lexers/archetype.py. The manipulation results in inefficient regular expression complexity. The attack is only possible with local access. The exploit has been released to the public and may be used for attacks. The project was informed of the problem early through an issue report but has not responded yet.

Attack profile

How easy it is to exploit

Attack vector
Local
Complexity
Low
Privileges needed
Low
User interaction
None

What an attacker can affect

Confidentiality
None
Integrity
None
Availability
Low

Exploit likelihood

0.16%Up 0.1 points since Mar 22, 2026
90%50%10%1%

What each source reports

CVE List Score used 4.8

pygments archetype.py AdlLexer redos

A security flaw has been discovered in pygments up to 2.19.2. The impacted element is the function AdlLexer of the file pygments/lexers/archetype.py. The manipulation results in inefficient regular expression complexity. The attack is only possible with local access. The exploit has been released to the public and may be used for attacks. The project was informed of the problem early through an issue report but has not responded yet.

Record
CVE-2026-4539
CVSS 4.0
4.8 MediumCVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P
CVSS 3.1
3.3 LowCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L/E:P/RL:X/RC:R
CVSS 3.0
3.3 LowCVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L/E:P/RL:X/RC:R
CVSS 2.0
1.7 AV:L/AC:L/Au:S/C:N/I:N/A:P/E:POC/RL:ND/RC:UR
Weakness
CWE-1333, CWE-400
Updated
2026-11-02
EUVDEUVD-2026-14287 4.8

A security flaw has been discovered in pygments up to 2.19.2. The impacted element is the function AdlLexer of the file pygments/lexers/archetype.py. The manipulation results in inefficient regular expression complexity. The attack is only possible with local access. The exploit has been released to the public and may be used for attacks. The project was informed of the problem early through an issue report but has not responded yet.

Record
EUVD-2026-14287
CVSS 4.0
4.8 MediumCVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P
Updated
2026-11-02
GitHub AdvisoriesGHSA-5239-wwwm-4pmq 1.9

Pygments has Regular Expression Denial of Service (ReDoS) due to Inefficient Regex for GUID Matching

A security flaw has been discovered in pygments before 2.20.0. The impacted element is the function AdlLexer of the file pygments/lexers/archetype.py. The manipulation results in inefficient regular expression complexity. The attack is only possible with local access. The exploit has been released to the public and may be used for attacks. The project was informed of the problem early through an issue report but has not responded yet.

Record
GHSA-5239-wwwm-4pmq
CVSS 4.0
1.9 LowCVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P
CVSS 3.1
3.3 LowCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
Weakness
CWE-400, CWE-1333
Updated
2026-11-02
NVD 1.9

A security flaw has been discovered in pygments up to 2.19.2. The impacted element is the function AdlLexer of the file pygments/lexers/archetype.py. The manipulation results in inefficient regular expression complexity. The attack is only possible with local access. The exploit has been released to the public and may be used for attacks. The project was informed of the problem early through an issue report but has not responded yet.

Record
CVE-2026-4539
CVSS 4.0
1.9 LowCVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS 3.1
3.3 LowCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
CVSS 2.0
1.7 LowAV:L/AC:L/Au:S/C:N/I:N/A:P
Weakness
CWE-400, CWE-1333
Updated
2026-11-02
OSV 1.9

pygments archetype.py AdlLexer redos

A security flaw has been discovered in pygments up to 2.19.2. The impacted element is the function AdlLexer of the file pygments/lexers/archetype.py. The manipulation results in inefficient regular expression complexity. The attack is only possible with local access. The exploit has been released to the public and may be used for attacks. The project was informed of the problem early through an issue report but has not responded yet.

Record
CVE-2026-4539
CVSS 4.0
1.9 LowCVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P
Weakness
CWE-1333, CWE-400
Updated
2026-11-02
OSVDEBIAN-CVE-2026-4539 1.9

A security flaw has been discovered in pygments up to 2.19.2. The impacted element is the function AdlLexer of the file pygments/lexers/archetype.py. The manipulation results in inefficient regular expression complexity. The attack is only possible with local access. The exploit has been released to the public and may be used for attacks. The project was informed of the problem early through an issue report but has not responded yet.

Record
DEBIAN-CVE-2026-4539
CVSS 4.0
1.9 LowCVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Updated
2026-11-02
Show 11 moreShow less
OSVGHSA-5239-wwwm-4pmq 1.9

Pygments has Regular Expression Denial of Service (ReDoS) due to Inefficient Regex for GUID Matching

A security flaw has been discovered in pygments before 2.20.0. The impacted element is the function AdlLexer of the file pygments/lexers/archetype.py. The manipulation results in inefficient regular expression complexity. The attack is only possible with local access. The exploit has been released to the public and may be used for attacks. The project was informed of the problem early through an issue report but has not responded yet.

Record
GHSA-5239-wwwm-4pmq
CVSS 4.0
1.9 LowCVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P
CVSS 3.1
3.3 LowCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
Weakness
CWE-1333, CWE-400
Updated
2026-11-02
OSVOESA-2026-1873 3.3

python-pygments security update

\

Security Fix(es):

A security flaw has been discovered in pygments up to 2.19.2. The impacted element is the function AdlLexer of the file pygments/lexers/archetype.py. The manipulation results in inefficient regular expression complexity. The attack is only possible with local access. The exploit has been released to the public and may be used for attacks. The project was informed of the problem early through an issue report but has not responded yet.(CVE-2026-4539)

Record
OESA-2026-1873
CVSS 3.1
3.3 LowCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
Updated
2026-11-02
OSVPYSEC-2026-2987 1.9

Pygments has Regular Expression Denial of Service (ReDoS) due to Inefficient Regex for GUID Matching

A security flaw has been discovered in pygments before 2.20.0. The impacted element is the function AdlLexer of the file pygments/lexers/archetype.py. The manipulation results in inefficient regular expression complexity. The attack is only possible with local access. The exploit has been released to the public and may be used for attacks. The project was informed of the problem early through an issue report but has not responded yet.

Record
PYSEC-2026-2987
CVSS 4.0
1.9 LowCVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P
CVSS 3.1
3.3 LowCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
Updated
2026-11-02
OSVUBUNTU-CVE-2026-4539 1.9

A security flaw has been discovered in pygments up to 2.19.2. The impacted element is the function AdlLexer of the file pygments/lexers/archetype.py. The manipulation results in inefficient regular expression complexity. The attack is only possible with local access. The exploit has been released to the public and may be used for attacks. The project was informed of the problem early through an issue report but has not responded yet.

Record
UBUNTU-CVE-2026-4539
CVSS 4.0
1.9 LowCVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P
CVSS 3.1
3.3 LowCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
Updated
2026-11-02
OSVMGASA-2026-0090 No score

Updated python-pygments packages fix security vulnerability

A security flaw in Pygments function AdlLexer in archetype.py stems from a regular expression having an inefficient, possibly exponential worst-case computational complexity that consumes excessive CPU cycles. (CVE-2026-4539)

Record
MGASA-2026-0090
Updated
2026-11-02
OSVopenSUSE-SU-2026:10476-1 No score

python311-Pygments-2.20.0-2.1 on GA media

These are all security issues fixed in the python311-Pygments-2.20.0-2.1 package on the GA media of openSUSE Tumbleweed.

Record
openSUSE-SU-2026:10476-1
Updated
2026-11-02
OSVopenSUSE-SU-2026:20931-1 No score

Security update for python-Pygments

This update for python-Pygments fixes the following issue:

  • CVE-2026-4539: Denial of Service via inefficient regular expression processing in AdlLexer (bsc#1260796).
Record
openSUSE-SU-2026:20931-1
Updated
2026-11-02
OSVSUSE-SU-2026:1666-1 No score

Security update for python-Pygments

This update for python-Pygments fixes the following issues:

  • CVE-2026-4539: inefficient regex for GUID and ID pattern matching can lead to archetype lexer ReDoS (bsc#1260796).
Record
SUSE-SU-2026:1666-1
Updated
2026-11-02
OSVSUSE-SU-2026:1667-1 No score

Security update for python-Pygments

This update for python-Pygments fixes the following issues:

  • CVE-2026-4539: inefficient regex for GUID and ID pattern matching can lead to archetype lexer ReDoS (bsc#1260796).
Record
SUSE-SU-2026:1667-1
Updated
2026-11-02
OSVSUSE-SU-2026:22058-1 No score

Security update for python-Pygments

This update for python-Pygments fixes the following issue:

  • CVE-2026-4539: Denial of Service via inefficient regular expression processing in AdlLexer (bsc#1260796).
Record
SUSE-SU-2026:22058-1
Updated
2026-11-02
OSVSUSE-SU-2026:22093-1 No score

Security update for python-Pygments

This update for python-Pygments fixes the following issue:

  • CVE-2026-4539: Denial of Service via inefficient regular expression processing in AdlLexer (bsc#1260796).
Record
SUSE-SU-2026:22093-1
Updated
2026-11-02

Affected packages

Affected packages
PackageAffectedFixed
pygments
PyPI
 before 2.20.0
2.20.0
pygments
Debian:12
 All versions, plus listed versions
2.14.0+dfsg-12.15.0+dfsg-12.15.1+dfsg-12.17.2+dfsg-12.18.0+dfsg-1
Show 4 moreShow less
2.18.0+dfsg-22.19.2+dfsg-12.20.0+dfsg-12.20.0+dfsg-2
 None known
pygments
Debian:13
 All versions, plus listed versions
2.18.0+dfsg-22.19.2+dfsg-12.20.0+dfsg-12.20.0+dfsg-2
 None known
pygments
Debian:14
 before 2.20.0+dfsg-1, plus listed versions
2.18.0+dfsg-22.19.2+dfsg-1
2.20.0+dfsg-1
pygments
PyPI
 before 2.20.0, plus listed versions
0.100.110.11.10.50.5.1
Show 45 moreShow less
0.60.70.7.10.80.8.10.91.01.11.1.11.21.2.11.2.21.31.3.11.41.51.61.6rc12.02.0.12.0.22.0rc12.12.1.12.1.22.1.32.10.02.11.02.11.12.11.22.12.02.13.02.14.02.15.02.15.12.16.02.16.12.17.02.17.12.17.22.18.02.19.02.19.12.19.22.2.0
2.20.0
python-pygments
Mageia:9
 before 2.15.1-1.1.mga9
2.15.1-1.1.mga9
python-pygments
openEuler:24.03-LTS-SP1
 before 2.17.2-2.oe2403sp1
2.17.2-2.oe2403sp1
python-pygments
openEuler:24.03-LTS-SP2
 before 2.17.2-2.oe2403sp2
2.17.2-2.oe2403sp2
python-pygments
openEuler:24.03-LTS-SP3
 before 2.17.2-2.oe2403sp3
2.17.2-2.oe2403sp3
python-pygments
openEuler:20.03-LTS-SP4
 before 2.5.2-7.oe2003sp4
2.5.2-7.oe2003sp4
Show 16 moreShow less
Affected packages
PackageAffectedFixed
python-pygments
openEuler:22.03-LTS-SP4
 before 2.10.0-5.oe2203sp4
2.10.0-5.oe2203sp4
python-pygments
openEuler:24.03-LTS
 before 2.17.2-2.oe2403
2.17.2-2.oe2403
python-Pygments
SUSE:Linux Micro 6.2
 before 2.19.1-160000.3.1
2.19.1-160000.3.1
python-Pygments
SUSE:Linux Enterprise Server 16.0
 before 2.19.1-160000.3.1
2.19.1-160000.3.1
python-Pygments
SUSE:Linux Enterprise Server for SAP applications 16.0
 before 2.19.1-160000.3.1
2.19.1-160000.3.1
pygments
Ubuntu:Pro:14.04:LTS
 All versions, plus listed versions
1.6+dfsg-11.6+dfsg-1build11.6+dfsg-1ubuntu11.6+dfsg-1ubuntu1.11.6+dfsg-1ubuntu1.1+esm1
 None known
pygments
Ubuntu:16.04:LTS
 All versions, plus listed versions
2.0.1+dfsg-1.1svn12.0.1+dfsg-1.1ubuntu12.1+dfsg-12.1+dfsg-1ubuntu0.12.1+dfsg-1ubuntu0.2
 None known
pygments
Ubuntu:18.04:LTS
 All versions, plus listed versions
2.2.0+dfsg-12.2.0+dfsg-1ubuntu0.12.2.0+dfsg-1ubuntu0.2
 None known
pygments
Ubuntu:20.04:LTS
 All versions, plus listed versions
2.3.1+dfsg-1ubuntu12.3.1+dfsg-1ubuntu22.3.1+dfsg-1ubuntu2.12.3.1+dfsg-1ubuntu2.2
 None known
pygments
Ubuntu:22.04:LTS
 All versions, plus listed versions
2.7.1+dfsg-2.12.10.0+dfsg-12.11.2+dfsg-22.11.2+dfsg-2ubuntu0.1
 None known
pygments
Ubuntu:24.04:LTS
 All versions, plus listed versions
2.15.1+dfsg-12.17.2+dfsg-1
 None known
pygments
Ubuntu:25.10
 All versions, plus listed versions
2.18.0+dfsg-2
 None known
pygments
Ubuntu:26.10
 All versions, plus listed versions
2.19.2+dfsg-12.20.0+dfsg-2
 None known
pygments
Ubuntu:26.04:LTS
 All versions, plus listed versions
2.18.0+dfsg-22.18.0+dfsg-2build12.19.2+dfsg-1
 None known
python-Pygments
openSUSE:Tumbleweed
 before 2.20.0-2.1
2.20.0-2.1
python-Pygments
openSUSE:Leap 16.0
 before 2.19.1-160000.3.1
2.19.1-160000.3.1

History

History
RecordedChangedSources
first indexedCVE List, EUVD, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2026-4539 is a medium vulnerability (CVSS 4.8) in pygments, published March 22, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.16%, the 5th percentile. Fixed in pygments 2.20.0.

References

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Left out here: 17 versions. The JSON record has them.

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