CVE-2026-115557: Distrust compromised intermediate certificates in ssl module
Noroxi assessment
Priority: Monitor (action score 37/100)
- The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
- Probability of exploitation in the next 30 days: 0.53% (FIRST EPSS).
- Anyone who can reach it over the internet can trigger it. No account or password is required. No special conditions are required; it is repeatable.
- Fixed version: Python Software Foundation CPython 3.11.18, 3.12.16, 3.13.18; azl3 python3 3.12.14-2 on Azure Linux 3.0 3.12.15-3.
Low priority for now. Upgrade to Python Software Foundation CPython 3.11.18, 3.12.16, 3.13.18; azl3 python3 3.12.14-2 on Azure Linux 3.0 3.12.15-3 or later.
Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it
Primary sources: NVD · CVE.org · FIRST EPSS
Python has added a denylist for known compromised certificates to the "ssl" module to ensure user safety even without certificate revocation configured. Known compromised certificates will automatically be rejected regardless of the SSLContext policy configuration.
- Published
- Oct 24, 2026
- Updated
- Nov 10, 2026
- EPSS
- 0.5% · 45th percentile
- CWE
- CWE-299
Report tools
Action score
37
Low priority for now.
- CVSS
- 37 / 40 · 9.4 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.5%
CISA SSVC decision
- Exploitation
- none
- Automatable
- no
- Technical impact
- total
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- —
- CNA · PSF
- 9.4
- NVD has not scored this yet; the score shown is the CNA’s.
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
Get told when this record changes
- Not in KEV: no record of exploitation in the wild
- No public exploit code on record
- A fix has been released
If any of these changes, we'll tell you in the daily email digest.
Is your version affected? Check itNoroxi analysis
What does it mean in your environment?
The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.
We use this product, ask for helpAffected systems
Is your version affected?
Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.
—
Versions reported by the vendor
Affected version ranges reported by the assigning authority (PSF). Independent of NVD's CPE analysis and usually ahead of it.
Python Software Foundation CPython
- before 3.11.18affected · python
- 3.12.0 and later · before 3.12.16affected · python
- 3.13.0 and later · before 3.13.18affected · python
- 3.14.0 and later · before 3.14.10affected · python
- 3.15.0 and later · before 3.15.2affected · python
- 3.16.0a1 and later · before 3.16.0affected · python
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Alpine:v3.21 | python3 | before 3.12.16-r0 | 3.12.16-r0 |
| Alpine:v3.24 | python3 | before 3.14.10-r0 | 3.14.10-r0 |
| Debian:12 | python3.11 | from 0 | — |
| Debian:13 | python3.13 | from 0 | — |
| Debian:14 | python3.14 | before 3.14.10-1 | 3.14.10-1 |
| Debian:14 | python3.15 | before 3.15.2-1 | 3.15.2-1 |
| openSUSE:Tumbleweed | python310 | before 3.10.22-3.1 | 3.10.22-3.1 |
| openSUSE:Tumbleweed | python315 | before 3.15.2-1.1 | 3.15.2-1.1 |
Same product
python software foundation: all recordsOther highest-scoring records for the same primary product.
- CVE-2025-4517Arbitrary writes via tarfile realpath overflow37Monitor
- CVE-2026-19445Use-after-free of a server-side SSLContext when sni_callback switches contexts36Monitor
- CVE-2026-6100Use-after-free in lzma.LZMADecompressor, bz2.BZ2Decompressor, and gzip.GzipFile after re-use under memory pressure36Monitor
Published before and after this one in the same product
- ← EarlierCVE-2026-19553Sep 30, 2026 · SSLContext.wrap_bio() missing validation of server_hostname parameter30Monitor
- ← EarlierCVE-2026-114583Oct 22, 2026 · tar filter allows writing outside destination via empty-named symlink27Monitor
- Later →CVE-2026-103995Oct 27, 2026 · Lenient parsing of integers for response body and chunk framing8Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| Python Software Foundation CPython | 3.11.18 | Vendor (CNA) |
| Python Software Foundation CPython | 3.12.16 | Vendor (CNA) |
| Python Software Foundation CPython | 3.13.18 | Vendor (CNA) |
| Python Software Foundation CPython | 3.14.10 | Vendor (CNA) |
| Python Software Foundation CPython | 3.15.2 | Vendor (CNA) |
| Python Software Foundation CPython | 3.16.0 | Vendor (CNA) |
| azl3 python3 3.12.14-2 on Azure Linux 3.0 | 3.12.15-3 · Release Notes | Microsoft (MSRC) |
| alpine:python3 | 3.12.16-r0 · Alpine:v3.23 | Package registry (OSV) |
| debian:python3.14 | 3.14.10-1 · Debian:14 | Package registry (OSV) |
| debian:python3.15 | 3.15.2-1 · Debian:14 | Package registry (OSV) |
| opensuse:python310 | 3.10.22-3.1 · openSUSE:Tumbleweed | Package registry (OSV) |
| opensuse:python315 | 3.15.2-1.1 · openSUSE:Tumbleweed | Package registry (OSV) |
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
- Published
- Fix recordedsame day
- TodayNov 14, 2026+21 d
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
- python/cpythoncommit 21a5089
- python/cpythoncommit 36cd295
- python/cpythoncommit 48d9b27
- python/cpythoncommit 7dd8b47
- python/cpythoncommit 98f0e4e
- python/cpythoncommit a17d9ef
- python/cpythoncommit af52b41
- python/cpythoncommit c7fd7ed
- python/cpythoncommit e2a9dd9
- python/cpythoncommit e4500d8
- python/cpythoncommit e4f63e6
- python/cpythoncommit e9bf2cf
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
- Christian Heimes (https://github.com/tiran)remediation developer
- Gregory P. Smith (https://github.com/gpshead)remediation reviewer
- T. Wouters (https://github.com/Yhg1s)remediation reviewer
- Emma Smith (https://github.com/emmatyping)remediation reviewer
- Seth Larson (https://github.com/sethmlarson)remediation reviewer
Not on record for this CVE: variant or chain candidate · public bounty program.
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- No account or password is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- Integrity
- Availability
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- P
- Scope
- X
Weakness class (CWE)
CWE-299 · Improper Check for Certificate RevocationCVSS vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/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
nvd-secondary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
MITRE has no CAPEC/ATT&CK mapping for this CWE.
Change log
- SSVC exploitation— → none
- Fix✗ → ✓
- Exploit maturity— → none
For records you follow, these changes also arrive as notifications. →
References
Show all references (17 more)Show less
- emudhra.we-have-a-problem.com/
- github.com/python/cpython/commit/21a50891ab4be2e9955239e625ae2b40c6b1854d
- github.com/python/cpython/commit/36cd295f32fc9ba19399e01abee91231440a41dd
- github.com/python/cpython/commit/48d9b2712cd52206c7a5882d0fdca4863ed65e93
- github.com/python/cpython/commit/7dd8b4736a1419750b94a388e6d158be15836fe6
- github.com/python/cpython/commit/98f0e4ed349f370dc8a00366da1a9797e11c9ed5
- github.com/python/cpython/commit/a17d9ef549008133eadf20689b1f4787902efe5b
- github.com/python/cpython/commit/af52b41afa4330fb38583db553631baa2f122f90
- github.com/python/cpython/commit/c7fd7edf7e0d122a3973cf676fae21b6aaa650a8
- github.com/python/cpython/commit/e2a9dd97ef9571c710ac0afaa834c8879aebce78
- github.com/python/cpython/commit/e4500d8a437ee5b988a5410cb9b59d177aa01370
- github.com/python/cpython/commit/e4f63e65a93cf44c14274aa987e644b8c003625e
- github.com/python/cpython/commit/e9bf2cf84eebf838a1edaa1c648c2b36345b99d3
- github.com/python/cpython/issues/160040
- github.com/python/cpython/pull/160042
- mail.python.org/archives/list/security-announce@python.org/thread/FNAJMZV6XQYLVPABNINDMF3VF66AYLW4/
- www.openwall.com/lists/oss-security/2026/10/24/5
Vendor advisories and official records. Exploit/PoC links are deliberately left out.