Algorithmic complexity vulnerability in the ssl.match_hostname function in Python 3.2.x…
Priority LOW 28CWE-399Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- — Not recorded in CVSS 2.0
- Attack complexity
- Medium
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- None · None · Partial
- Fix status
- Partial Red Hat: 19 fixed, 8 without a fix
Attack profile from CVSS 2.0 · NVD. Fix status from CNA and Red Hat. Impact type from CWE-399 and the CVSS impact.
Summary
Algorithmic complexity vulnerability in the ssl.match_hostname function in Python 3.2.x, 3.3.x, and earlier, and unspecified versions of python-backports-ssl_match_hostname as used for older Python versions, allows remote attackers to cause a denial of service (CPU consumption) via multiple wildcard characters in the common name in a certificate.
Why it matters now
EPSS 0.04857 92nd percentileScored 2026-11-07
Fix Partial Red Hat: 4 advisoriesRed Hat: 19 fixed, 8 without a fix
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| — | — | all versions | — | No fix listed | CNA |
- — Vendor— Affected all versions Fixed in — No fix listed CNA
CPE configurations NVD · 12
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:python:python:3.2.0:*:*:*:*:*:*:* | 3.2.0 | Vulnerable | python-pillow |
| cpe:2.3:a:python:python:3.2.1:*:*:*:*:*:*:* | 3.2.1 | Vulnerable | python-pillow |
| cpe:2.3:a:python:python:3.2.2:*:*:*:*:*:*:* | 3.2.2 | Vulnerable | python-pillow |
| cpe:2.3:a:python:python:3.2.3:*:*:*:*:*:*:* | 3.2.3 | Vulnerable | python-pillow |
| cpe:2.3:a:python:python:3.2.4:*:*:*:*:*:*:* | 3.2.4 | Vulnerable | python-pillow |
| cpe:2.3:a:python:python:3.2.5:*:*:*:*:*:*:* | 3.2.5 | Vulnerable | python-pillow |
| cpe:2.3:a:python:python:3.3.0:*:*:*:*:*:*:* | 3.3.0 | Vulnerable | python-pillow |
| cpe:2.3:a:python:python:3.3.1:*:*:*:*:*:*:* | 3.3.1 | Vulnerable | python-pillow |
| cpe:2.3:a:python:python:3.3.2:*:*:*:*:*:*:* | 3.3.2 | Vulnerable | python-pillow |
| cpe:2.3:o:canonical:ubuntu_linux:12.04:-:lts:*:*:*:*:* | 12.04 | Vulnerable | Canonical |
- cpe:2.3:a:python:python:3.2.0:*:*:*:*:*:*:* Versions 3.2.0 Vulnerable ·python-pillow
- cpe:2.3:a:python:python:3.2.1:*:*:*:*:*:*:* Versions 3.2.1 Vulnerable ·python-pillow
- cpe:2.3:a:python:python:3.2.2:*:*:*:*:*:*:* Versions 3.2.2 Vulnerable ·python-pillow
- cpe:2.3:a:python:python:3.2.3:*:*:*:*:*:*:* Versions 3.2.3 Vulnerable ·python-pillow
- cpe:2.3:a:python:python:3.2.4:*:*:*:*:*:*:* Versions 3.2.4 Vulnerable ·python-pillow
- cpe:2.3:a:python:python:3.2.5:*:*:*:*:*:*:* Versions 3.2.5 Vulnerable ·python-pillow
- cpe:2.3:a:python:python:3.3.0:*:*:*:*:*:*:* Versions 3.3.0 Vulnerable ·python-pillow
- cpe:2.3:a:python:python:3.3.1:*:*:*:*:*:*:* Versions 3.3.1 Vulnerable ·python-pillow
- cpe:2.3:a:python:python:3.3.2:*:*:*:*:*:*:* Versions 3.3.2 Vulnerable ·python-pillow
- cpe:2.3:o:canonical:ubuntu_linux:12.04:-:lts:*:*:*:*:* Versions 12.04 Vulnerable ·Canonical
Remediation
Red Hat 4 advisories
- RHSA-2016:1166 Released 2016-05-31 · Red Hat rating Moderatepython27 security, bug fix, and enhancement update
- Red Hat Software Collections for Red Hat Enterprise Linux Server (v. 6) python27-1.1-25.el6, python27-PyYAML-3.10-14.el6, python27-numpy-1:1.7.1-10.el6 +18
- Red Hat Software Collections for Red Hat Enterprise Linux Server (v. 7) python27-1.1-25.el7, python27-PyYAML-3.10-14.el7, python27-numpy-1:1.7.1-10.el7 +17
- Red Hat Software Collections for Red Hat Enterprise Linux Server EUS (v. 6.6) python27-1.1-25.el6, python27-PyYAML-3.10-14.el6, python27-numpy-1:1.7.1-10.el6 +18
- Red Hat Software Collections for Red Hat Enterprise Linux Server EUS (v. 6.7) python27-1.1-25.el6, python27-PyYAML-3.10-14.el6, python27-numpy-1:1.7.1-10.el6 +18
- Red Hat Software Collections for Red Hat Enterprise Linux Server EUS (v. 7.1) python27-1.1-25.el7, python27-PyYAML-3.10-14.el7, python27-numpy-1:1.7.1-10.el7 +17
- Red Hat Software Collections for Red Hat Enterprise Linux Server EUS (v. 7.2) python27-1.1-25.el7, python27-PyYAML-3.10-14.el7, python27-numpy-1:1.7.1-10.el7 +17
- Red Hat Software Collections for Red Hat Enterprise Linux Workstation (v. 6) python27-1.1-25.el6, python27-PyYAML-3.10-14.el6, python27-numpy-1:1.7.1-10.el6 +18
- Red Hat Software Collections for Red Hat Enterprise Linux Workstation (v. 7) python27-1.1-25.el7, python27-PyYAML-3.10-14.el7, python27-numpy-1:1.7.1-10.el7 +17
- RHSA-2015:0042 Released 2015-01-13 · Red Hat rating Lowcloud-init security, bug fix, and enhancement update
- Red Hat Common for RHEL Client (v. 6) python-backports-1.0-3.el6, python-backports-ssl_match_hostname-3.4.0.2-1.el6, python-six-1.6.1-1.el6 +1
- Red Hat Common for RHEL Compute Node (v. 6) python-backports-1.0-3.el6, python-backports-ssl_match_hostname-3.4.0.2-1.el6, python-six-1.6.1-1.el6 +1
- Red Hat Common for RHEL Server (v. 6) cloud-init-0.7.5-1.el6, python-backports-1.0-3.el6, python-backports-ssl_match_hostname-3.4.0.2-1.el6 +5
- Red Hat Common for RHEL Workstation (v. 6) python-backports-1.0-3.el6, python-backports-ssl_match_hostname-3.4.0.2-1.el6, python-six-1.6.1-1.el6 +1
- RHSA-2014:1690 Released 2014-10-22 · Red Hat rating Lowpython-backports-ssl_match_hostname security update
- Red Hat Enterprise Linux OpenStack Platform 4.0 python-backports-ssl_match_hostname-3.4.0.2-1.el6
Show 1 more Red Hat advisories
- RHSA-2014:1263 Released 2014-09-18 · Red Hat rating LowRed Hat Storage 2.1 security, bug fix, and enhancement update
- Red Hat Storage Console 2.1 rhsc-2.1.2-0.40.el6rhs, rhsc-backend-2.1.2-0.40.el6rhs, rhsc-branding-rhs-2.1.5-2.0.el6rhs +6
- Red Hat Storage Native Client for Red Hat Enterprise Linux 5 glusterfs-3.4.0.68rhs-1.el5, glusterfs-api-3.4.0.68rhs-1.el5, glusterfs-api-devel-3.4.0.68rhs-1.el5 +4
- Red Hat Storage Native Client for Red Hat Enterprise Linux 6 glusterfs-3.4.0.68rhs-1.el6, glusterfs-api-3.4.0.68rhs-1.el6, glusterfs-api-devel-3.4.0.68rhs-1.el6 +4
- Red Hat Storage Server 2.1 glusterfs-3.4.0.68rhs-1.el6rhs, glusterfs-api-3.4.0.68rhs-1.el6rhs, glusterfs-api-devel-3.4.0.68rhs-1.el6rhs +9
Vendor assessments
Red Hat
Red Hat rating: Low. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 7 | Affected | No fix planned: Will not fix |
| Red Hat Enterprise Linux OpenStack Platform 5 (Icehouse) | Affected | No fix yet |
| Red Hat Enterprise Linux OpenStack Platform 6 (Juno) | Affected | No fix yet |
| Red Hat Enterprise Linux OpenStack Platform 7 (Kilo) | Affected | No fix yet |
| Red Hat OpenShift Enterprise 2 | Affected | No fix yet |
| Red Hat OpenStack Platform 3 | Affected | No fix planned: Will not fix |
| Red Hat OpenStack Platform 4 | Affected | No fix planned: Will not fix |
| Red Hat Software Collections | Affected | No fix planned: Will not fix |
| Red Hat Common for RHEL Client (v. 6) | Fixed | RHSA-2015:0042 |
| Red Hat Common for RHEL Compute Node (v. 6) | Fixed | RHSA-2015:0042 |
| Red Hat Common for RHEL Server (v. 6) | Fixed | RHSA-2015:0042 |
| Red Hat Common for RHEL Workstation (v. 6) | Fixed | RHSA-2015:0042 |
| Red Hat Enterprise Linux OpenStack Platform 4.0 | Fixed | RHSA-2014:1690 |
| Red Hat Satellite 6.2 | Fixed | — |
| Red Hat Satellite Capsule 6.2 | Fixed | — |
| Red Hat Software Collections for Red Hat Enterprise Linux Server (v. 6) | Fixed | RHSA-2016:1166 |
| Red Hat Software Collections for Red Hat Enterprise Linux Server (v. 7) | Fixed | RHSA-2016:1166 |
| Red Hat Software Collections for Red Hat Enterprise Linux Server EUS (v. 6.6) | Fixed | RHSA-2016:1166 |
| Red Hat Software Collections for Red Hat Enterprise Linux Server EUS (v. 6.7) | Fixed | RHSA-2016:1166 |
| Red Hat Software Collections for Red Hat Enterprise Linux Server EUS (v. 7.1) | Fixed | RHSA-2016:1166 |
| Red Hat Software Collections for Red Hat Enterprise Linux Server EUS (v. 7.2) | Fixed | RHSA-2016:1166 |
| Red Hat Software Collections for Red Hat Enterprise Linux Workstation (v. 6) | Fixed | RHSA-2016:1166 |
| Red Hat Software Collections for Red Hat Enterprise Linux Workstation (v. 7) | Fixed | RHSA-2016:1166 |
| Red Hat Storage Console 2.1 | Fixed | RHSA-2014:1263 |
| Red Hat Storage Native Client for Red Hat Enterprise Linux 5 | Fixed | RHSA-2014:1263 |
| Red Hat Storage Native Client for Red Hat Enterprise Linux 6 | Fixed | RHSA-2014:1263 |
| Red Hat Storage Server 2.1 | Fixed | RHSA-2014:1263 |
Not affected: 8 products
- Red Hat Enterprise Linux 5
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux OpenStack Platform 5 (Icehouse)
- Red Hat Enterprise MRG 2
- Red Hat Satellite 6
- Red Hat Software Collections
- Red Hat Subscription Asset Manager
Timeline
- 2026-10-02 Threatist record created from CVE-2013-2099
- 2026-10-03 Alias added: GHSA-cqcg-qrcv-vr6v
References
Other 2
- https://bugzilla.redhat.com/show_bug.cgi?id=963260
- [oss-security] 20130515 Re: CVE Request (minor) -- Python 3.2: DoS when matching certificate with many '*' wildcard characters {was: CVE Request (minor) -- python-backports-ssl_match_hostname: Denial of service when matching certificate with many '*' wildcard characters }
Sources
- CVE-2013-2099 · CVE Program
- CVE-2013-2099 · NVD
- FIRST EPSS
- GHSA-cqcg-qrcv-vr6v · GitHub Advisory Database · CC BY 4.0
- CVE-2013-2099 · Red Hat security data · CC BY 4.0
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