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CVE-2026-4926

path-to-regexp vulnerable to Denial of Service via sequential optional groups

7.5 HighFix available

Impact:

A bad regular expression is generated any time you have multiple sequential optional groups (curly brace syntax), such as {a}{b}{c}:z. The generated regex grows exponentially with the number of groups, causing denial of service.

Patches:

Fixed in version 8.4.0.

Workarounds:

Limit the number of sequential optional groups in route patterns. Avoid passing user-controlled input as route patterns.

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
Low
Privileges needed
None
User interaction
None

What an attacker can affect

Confidentiality
None
Integrity
None
Availability
High

Exploit likelihood

0.80%Up 0.8 points since Mar 27, 2026
90%50%10%1%

What each source reports

CVE List Score used 7.5

path-to-regexp vulnerable to Denial of Service via sequential optional groups

Impact:

A bad regular expression is generated any time you have multiple sequential optional groups (curly brace syntax), such as {a}{b}{c}:z. The generated regex grows exponentially with the number of groups, causing denial of service.

Patches:

Fixed in version 8.4.0.

Workarounds:

Limit the number of sequential optional groups in route patterns. Avoid passing user-controlled input as route patterns.

Record
CVE-2026-4926
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness
CWE-400, CWE-1333, CWE-1333
Updated
2026-11-02
EUVDEUVD-2026-16324 7.5

Impact:

A bad regular expression is generated any time you have multiple sequential optional groups (curly brace syntax), such as {a}{b}{c}:z. The generated regex grows exponentially with the number of groups, causing denial of service.

Patches:

Fixed in version 8.4.0.

Workarounds:

Limit the number of sequential optional groups in route patterns. Avoid passing user-controlled input as route patterns.

Record
EUVD-2026-16324
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Updated
2026-11-02
GitHub AdvisoriesGHSA-j3q9-mxjg-w52f 7.5

path-to-regexp vulnerable to Denial of Service via sequential optional groups

Impact

A bad regular expression is generated any time you have multiple sequential optional groups (curly brace syntax), such as {a}{b}{c}:z. The generated regex grows exponentially with the number of groups, causing denial of service.

Patches

Fixed in version 8.4.0.

Workarounds

Limit the number of sequential optional groups in route patterns. Avoid passing user-controlled input as route patterns.

Record
GHSA-j3q9-mxjg-w52f
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness
CWE-400, CWE-1333
Updated
2026-11-02
NVD 7.5

Impact:

A bad regular expression is generated any time you have multiple sequential optional groups (curly brace syntax), such as {a}{b}{c}:z. The generated regex grows exponentially with the number of groups, causing denial of service.

Patches:

Fixed in version 8.4.0.

Workarounds:

Limit the number of sequential optional groups in route patterns. Avoid passing user-controlled input as route patterns.

Record
CVE-2026-4926
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness
CWE-400, CWE-1333
Updated
2026-11-02
OSV 7.5

path-to-regexp vulnerable to Denial of Service via sequential optional groups

Impact:

A bad regular expression is generated any time you have multiple sequential optional groups (curly brace syntax), such as {a}{b}{c}:z. The generated regex grows exponentially with the number of groups, causing denial of service.

Patches:

Fixed in version 8.4.0.

Workarounds:

Limit the number of sequential optional groups in route patterns. Avoid passing user-controlled input as route patterns.

Record
CVE-2026-4926
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness
CWE-1333, CWE-400
Updated
2026-11-02
OSVDEBIAN-CVE-2026-4926 7.5

Impact: A bad regular expression is generated any time you have multiple sequential optional groups (curly brace syntax), such as {a}{b}{c}:z. The generated regex grows exponentially with the number of groups, causing denial of service. Patches: Fixed in version 8.4.0. Workarounds: Limit the number of sequential optional groups in route patterns. Avoid passing user-controlled input as route patterns.

Record
DEBIAN-CVE-2026-4926
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Updated
2026-11-02
Show 5 moreShow less
OSVGHSA-j3q9-mxjg-w52f 7.5

path-to-regexp vulnerable to Denial of Service via sequential optional groups

Impact

A bad regular expression is generated any time you have multiple sequential optional groups (curly brace syntax), such as {a}{b}{c}:z. The generated regex grows exponentially with the number of groups, causing denial of service.

Patches

Fixed in version 8.4.0.

Workarounds

Limit the number of sequential optional groups in route patterns. Avoid passing user-controlled input as route patterns.

Record
GHSA-j3q9-mxjg-w52f
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness
CWE-1333, CWE-400
Updated
2026-11-02
OSVRHSA-2026:24761 7.8

Red Hat Security Advisory: Red Hat Ansible Automation Platform 2.5 Product Security and Bug Fix Update

Record
RHSA-2026:24761
CVSS 3.1
7.8 HighCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H
Updated
2026-11-02
OSVRHSA-2026:24762 8.1

Red Hat Security Advisory: Red Hat Ansible Automation Platform 2.6 Product Security and Bug Fix Update

Record
RHSA-2026:24762
CVSS 3.1
8.1 HighCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Updated
2026-11-02
OSVROOT-APP-NPM-CVE-2026-4926 7.5

CVE-2026-4926 in path-to-regexp - Patched by Root

Root has patched CVE-2026-4926 in the path-to-regexp package for Root:npm. Multiple fixed versions available.

Record
ROOT-APP-NPM-CVE-2026-4926
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Updated
2026-11-02
OSVUBUNTU-CVE-2026-4926 7.5

Impact: A bad regular expression is generated any time you have multiple sequential optional groups (curly brace syntax), such as {a}{b}{c}:z. The generated regex grows exponentially with the number of groups, causing denial of service. Patches: Fixed in version 8.4.0. Workarounds: Limit the number of sequential optional groups in route patterns. Avoid passing user-controlled input as route patterns.

Record
UBUNTU-CVE-2026-4926
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Updated
2026-11-02

Affected products

Show 41 moreShow less

Affected packages

Affected packages
PackageAffectedFixed
path-to-regexp
npm
8.0.0 up to 8.4.0
8.4.0
node-path-to-regexp
Debian:12
All versions, plus listed versions
6.2.1-16.3.0-18.3.0-18.4.0-18.4.1-18.4.2-1
None known
node-path-to-regexp
Debian:13
All versions, plus listed versions
6.3.0-18.3.0-18.4.0-18.4.1-18.4.2-1
None known
node-path-to-regexp
Debian:14
before 8.4.0-1, plus listed versions
6.3.0-18.3.0-1
8.4.0-1
automation-gateway-server
Red Hat:ansible_automation_platform:2.5::el8
From an advisory covering 16 CVEs
before 0:2.5.20260422-3.el8ap
0:2.5.20260422-3.el8ap
automation-gateway-server
Red Hat:ansible_automation_platform:2.5::el9
From an advisory covering 16 CVEs
before 0:2.5.20260422-3.el9ap
0:2.5.20260422-3.el9ap
python3.12-click
Red Hat:ansible_automation_platform_developer:2.5::el8
From an advisory covering 16 CVEs
before 0:8.3.3-1.el8ap
0:8.3.3-1.el8ap
python3.12-click
Red Hat:ansible_automation_platform_inside:2.5::el8
From an advisory covering 16 CVEs
before 0:8.3.3-1.el8ap
0:8.3.3-1.el8ap
python3.12-click
Red Hat:ansible_automation_platform:2.5::el8
From an advisory covering 16 CVEs
before 0:8.3.3-1.el8ap
0:8.3.3-1.el8ap
python3.12-click
Red Hat:ansible_automation_platform_developer:2.5::el9
From an advisory covering 16 CVEs
before 0:8.3.3-1.el9ap
0:8.3.3-1.el9ap
Show 63 moreShow less
Affected packages
PackageAffectedFixed
python3.12-click
Red Hat:ansible_automation_platform_inside:2.5::el9
From an advisory covering 16 CVEs
before 0:8.3.3-1.el9ap
0:8.3.3-1.el9ap
python3.12-click
Red Hat:ansible_automation_platform:2.5::el9
From an advisory covering 16 CVEs
before 0:8.3.3-1.el9ap
0:8.3.3-1.el9ap
automation-controller-venv-tower
Red Hat:ansible_automation_platform:2.5::el8
From an advisory covering 16 CVEs
before 0:4.6.29-2.el8ap
0:4.6.29-2.el8ap
automation-controller-venv-tower
Red Hat:ansible_automation_platform:2.5::el9
From an advisory covering 16 CVEs
before 0:4.6.29-2.el9ap
0:4.6.29-2.el9ap
receptor
Red Hat:ansible_automation_platform_developer:2.5::el8
From an advisory covering 16 CVEs
before 0:1.6.5-1.el8ap
0:1.6.5-1.el8ap
receptor
Red Hat:ansible_automation_platform_inside:2.5::el8
From an advisory covering 16 CVEs
before 0:1.6.5-1.el8ap
0:1.6.5-1.el8ap
automation-gateway-proxy-server
Red Hat:ansible_automation_platform:2.5::el8
From an advisory covering 16 CVEs
before 0:2.5.10-6.el8ap
0:2.5.10-6.el8ap
receptor
Red Hat:ansible_automation_platform:2.5::el8
From an advisory covering 16 CVEs
before 0:1.6.5-1.el8ap
0:1.6.5-1.el8ap
receptor
Red Hat:ansible_automation_platform_developer:2.5::el9
From an advisory covering 16 CVEs
before 0:1.6.5-1.el9ap
0:1.6.5-1.el9ap
receptor
Red Hat:ansible_automation_platform_inside:2.5::el9
From an advisory covering 16 CVEs
before 0:1.6.5-1.el9ap
0:1.6.5-1.el9ap
automation-gateway-proxy-server
Red Hat:ansible_automation_platform:2.5::el9
From an advisory covering 16 CVEs
before 0:2.6.14-3.el9ap
0:2.6.14-3.el9ap
receptor
Red Hat:ansible_automation_platform:2.5::el9
From an advisory covering 16 CVEs
before 0:1.6.5-1.el9ap
0:1.6.5-1.el9ap
python3.12-cryptography
Red Hat:ansible_automation_platform_developer:2.5::el8
From an advisory covering 16 CVEs
before 0:46.0.7-1.el8ap
0:46.0.7-1.el8ap
python3.12-cryptography
Red Hat:ansible_automation_platform_inside:2.5::el8
From an advisory covering 16 CVEs
before 0:46.0.7-1.el8ap
0:46.0.7-1.el8ap
python3.12-cryptography
Red Hat:ansible_automation_platform:2.5::el8
From an advisory covering 16 CVEs
before 0:46.0.7-1.el8ap
0:46.0.7-1.el8ap
python3.12-cryptography
Red Hat:ansible_automation_platform_developer:2.5::el9
From an advisory covering 16 CVEs
before 0:46.0.7-1.el9ap
0:46.0.7-1.el9ap
python3.12-cryptography
Red Hat:ansible_automation_platform_inside:2.5::el9
From an advisory covering 16 CVEs
before 0:46.0.7-1.el9ap
0:46.0.7-1.el9ap
python3.12-cryptography
Red Hat:ansible_automation_platform:2.5::el9
From an advisory covering 16 CVEs
before 0:46.0.7-1.el9ap
0:46.0.7-1.el9ap
python3.12-pillow
Red Hat:ansible_automation_platform:2.5::el8
From an advisory covering 16 CVEs
before 0:12.2.0-1.el8ap
0:12.2.0-1.el8ap
python3.12-pillow
Red Hat:ansible_automation_platform:2.5::el9
From an advisory covering 16 CVEs
before 0:12.2.0-1.el9ap
0:12.2.0-1.el9ap
automation-platform-ui
Red Hat:ansible_automation_platform:2.6::el9
From an advisory covering 12 CVEs
before 0:2.6.9-1.el9ap
0:2.6.9-1.el9ap
python3-click
Red Hat:ansible_automation_platform_developer:2.6::el10
From an advisory covering 12 CVEs
before 0:8.3.3-1.el10ap
0:8.3.3-1.el10ap
python3-click
Red Hat:ansible_automation_platform:2.6::el10
From an advisory covering 12 CVEs
before 0:8.3.3-1.el10ap
0:8.3.3-1.el10ap
python3.12-click
Red Hat:ansible_automation_platform_developer:2.6::el9
From an advisory covering 12 CVEs
before 0:8.3.3-1.el9ap
0:8.3.3-1.el9ap
python3.12-click
Red Hat:ansible_automation_platform_inside:2.6::el9
From an advisory covering 12 CVEs
before 0:8.3.3-1.el9ap
0:8.3.3-1.el9ap
python3.12-click
Red Hat:ansible_automation_platform:2.6::el9
From an advisory covering 12 CVEs
before 0:8.3.3-1.el9ap
0:8.3.3-1.el9ap
automation-controller
Red Hat:ansible_automation_platform_developer:2.6::el9
From an advisory covering 12 CVEs
before 0:4.7.12-1.el9ap
0:4.7.12-1.el9ap
automation-controller-cli
Red Hat:ansible_automation_platform_developer:2.6::el9
From an advisory covering 12 CVEs
before 0:4.7.12-1.el9ap
0:4.7.12-1.el9ap
automation-controller
Red Hat:ansible_automation_platform:2.6::el9
From an advisory covering 12 CVEs
before 0:4.7.12-1.el9ap
0:4.7.12-1.el9ap
automation-controller-cli
Red Hat:ansible_automation_platform:2.6::el9
From an advisory covering 12 CVEs
before 0:4.7.12-1.el9ap
0:4.7.12-1.el9ap
automation-controller-server
Red Hat:ansible_automation_platform:2.6::el9
From an advisory covering 12 CVEs
before 0:4.7.12-1.el9ap
0:4.7.12-1.el9ap
automation-controller-ui
Red Hat:ansible_automation_platform:2.6::el9
From an advisory covering 12 CVEs
before 0:4.7.12-1.el9ap
0:4.7.12-1.el9ap
automation-controller-venv-tower
Red Hat:ansible_automation_platform:2.6::el9
From an advisory covering 12 CVEs
before 0:4.7.12-1.el9ap
0:4.7.12-1.el9ap
receptor
Red Hat:ansible_automation_platform:2.6::el10
From an advisory covering 12 CVEs
before 0:1.6.5-1.el10ap
0:1.6.5-1.el10ap
receptor-debuginfo
Red Hat:ansible_automation_platform:2.6::el10
From an advisory covering 12 CVEs
before 0:1.6.5-1.el10ap
0:1.6.5-1.el10ap
receptor-debugsource
Red Hat:ansible_automation_platform:2.6::el10
From an advisory covering 12 CVEs
before 0:1.6.5-1.el10ap
0:1.6.5-1.el10ap
receptorctl
Red Hat:ansible_automation_platform:2.6::el10
From an advisory covering 12 CVEs
before 0:1.6.5-1.el10ap
0:1.6.5-1.el10ap
receptor
Red Hat:ansible_automation_platform_developer:2.6::el9
From an advisory covering 12 CVEs
before 0:1.6.5-1.el9ap
0:1.6.5-1.el9ap
receptorctl
Red Hat:ansible_automation_platform_developer:2.6::el9
From an advisory covering 12 CVEs
before 0:1.6.5-1.el9ap
0:1.6.5-1.el9ap
receptor
Red Hat:ansible_automation_platform_inside:2.6::el9
From an advisory covering 12 CVEs
before 0:1.6.5-1.el9ap
0:1.6.5-1.el9ap
receptorctl
Red Hat:ansible_automation_platform_inside:2.6::el9
From an advisory covering 12 CVEs
before 0:1.6.5-1.el9ap
0:1.6.5-1.el9ap
automation-gateway-proxy
Red Hat:ansible_automation_platform:2.6::el9
From an advisory covering 12 CVEs
before 0:2.6.14-3.el9ap
0:2.6.14-3.el9ap
automation-gateway-proxy-debugsource
Red Hat:ansible_automation_platform:2.6::el9
From an advisory covering 12 CVEs
before 0:2.6.14-3.el9ap
0:2.6.14-3.el9ap
automation-gateway-proxy-server
Red Hat:ansible_automation_platform:2.6::el9
From an advisory covering 12 CVEs
before 0:2.6.14-3.el9ap
0:2.6.14-3.el9ap
automation-gateway-proxy-server-debuginfo
Red Hat:ansible_automation_platform:2.6::el9
From an advisory covering 12 CVEs
before 0:2.6.14-3.el9ap
0:2.6.14-3.el9ap
receptor
Red Hat:ansible_automation_platform:2.6::el9
From an advisory covering 12 CVEs
before 0:1.6.5-1.el9ap
0:1.6.5-1.el9ap
receptor-debuginfo
Red Hat:ansible_automation_platform:2.6::el9
From an advisory covering 12 CVEs
before 0:1.6.5-1.el9ap
0:1.6.5-1.el9ap
receptor-debugsource
Red Hat:ansible_automation_platform:2.6::el9
From an advisory covering 12 CVEs
before 0:1.6.5-1.el9ap
0:1.6.5-1.el9ap
receptorctl
Red Hat:ansible_automation_platform:2.6::el9
From an advisory covering 12 CVEs
before 0:1.6.5-1.el9ap
0:1.6.5-1.el9ap
python3.12-cryptography
Red Hat:ansible_automation_platform_developer:2.6::el9
From an advisory covering 12 CVEs
before 0:46.0.7-1.el9ap
0:46.0.7-1.el9ap
python3.12-cryptography-debuginfo
Red Hat:ansible_automation_platform_developer:2.6::el9
From an advisory covering 12 CVEs
before 0:46.0.7-1.el9ap
0:46.0.7-1.el9ap
python3.12-cryptography-debugsource
Red Hat:ansible_automation_platform_developer:2.6::el9
From an advisory covering 12 CVEs
before 0:46.0.7-1.el9ap
0:46.0.7-1.el9ap
python3.12-cryptography
Red Hat:ansible_automation_platform_inside:2.6::el9
From an advisory covering 12 CVEs
before 0:46.0.7-1.el9ap
0:46.0.7-1.el9ap
python3.12-cryptography-debuginfo
Red Hat:ansible_automation_platform_inside:2.6::el9
From an advisory covering 12 CVEs
before 0:46.0.7-1.el9ap
0:46.0.7-1.el9ap
python3.12-cryptography-debugsource
Red Hat:ansible_automation_platform_inside:2.6::el9
From an advisory covering 12 CVEs
before 0:46.0.7-1.el9ap
0:46.0.7-1.el9ap
python3.12-cryptography
Red Hat:ansible_automation_platform:2.6::el9
From an advisory covering 12 CVEs
before 0:46.0.7-1.el9ap
0:46.0.7-1.el9ap
python3.12-cryptography-debuginfo
Red Hat:ansible_automation_platform:2.6::el9
From an advisory covering 12 CVEs
before 0:46.0.7-1.el9ap
0:46.0.7-1.el9ap
python3.12-cryptography-debugsource
Red Hat:ansible_automation_platform:2.6::el9
From an advisory covering 12 CVEs
before 0:46.0.7-1.el9ap
0:46.0.7-1.el9ap
python3.12-pillow
Red Hat:ansible_automation_platform:2.6::el9
From an advisory covering 12 CVEs
before 0:12.2.0-1.el9ap
0:12.2.0-1.el9ap
python3.12-pillow-debuginfo
Red Hat:ansible_automation_platform:2.6::el9
From an advisory covering 12 CVEs
before 0:12.2.0-1.el9ap
0:12.2.0-1.el9ap
python3.12-pillow-debugsource
Red Hat:ansible_automation_platform:2.6::el9
From an advisory covering 12 CVEs
before 0:12.2.0-1.el9ap
0:12.2.0-1.el9ap
path-to-regexp
Root:npm
before 8.3.0-aikido.2
8.3.0-aikido.28.3.0-aikido.38.2.0-aikido.38.3.0-aikido.4
@rootio/path-to-regexp
Root:npm
before 8.3.0-root.io.1
8.3.0-root.io.18.3.0-root.io.28.3.0-root.io.38.2.0-root.io.18.2.0-root.io.38.3.0-root.io.4

History

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

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

In short

CVE-2026-4926 is a high vulnerability (CVSS 7.5) in Path-to-regexp, published March 26, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.80%, the 57th percentile. Fixed in path-to-regexp 8.4.0.

References

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