CVE-2024-5642: Buffer overread when using an empty list with SSLContext.set_npn_protocols()
Noroxi assessment
Priority: Monitor (action score 26/100)
- 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: 0.74% (FIRST EPSS); higher than 54.7% of all records.
- Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
- Fixed version: Python Software Foundation CPython 3.10.0b1, 3.9.24.
- Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).
Low priority for now. Upgrade to Python Software Foundation CPython 3.10.0b1, 3.9.24 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
CPython 3.9 and earlier doesn't disallow configuring an empty list ("[]") for SSLContext.set_npn_protocols() which is an invalid value for the underlying OpenSSL API. This results in a buffer over-read when NPN is used (see CVE-2024-5535 for OpenSSL). This vulnerability is of low severity due to NPN being not widely used and specifying an empty list likely being uncommon in-practice (typically a protocol name would be configured).
- Published
- Jun 27, 2024
- Updated
- Jul 31, 2026
- EPSS
- 0.7% · 54th percentile
- CWE
- —
Report tools
Action score
26
Monitor
Low priority for now.
- CVSS
- 26 / 40 · 6.5 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.7%
CISA SSVC decision
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
Vulnrichment: CISA's decision-tree inputs.
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.
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Noroxi 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 3.9.24affected · python
- 3.10.0a1 and later · before 3.10.0b1affected · python
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| AlmaLinux:8 | python39 | before 3.9.25-2.module_el8.10.0+4083+53cad1fb | 3.9.25-2.module_el8.10.0+4083+53cad1fb |
| AlmaLinux:8 | python39-attrs | before 20.3.0-2.module_el8.6.0+2780+a40f65e1 | 20.3.0-2.module_el8.6.0+2780+a40f65e1 |
| AlmaLinux:8 | python39-cffi | before 1.14.3-2.module_el8.6.0+2780+a40f65e1 | 1.14.3-2.module_el8.6.0+2780+a40f65e1 |
| AlmaLinux:8 | python39-cffi | before 1.14.3-2.module_el8.6.0+3248+c431e88c | 1.14.3-2.module_el8.6.0+3248+c431e88c |
| AlmaLinux:8 | python39-chardet | before 3.0.4-19.module_el8.6.0+2780+a40f65e1 | 3.0.4-19.module_el8.6.0+2780+a40f65e1 |
| AlmaLinux:8 | python39-cryptography | before 3.3.1-3.module_el8.10.0+3765+2f9a457d | 3.3.1-3.module_el8.10.0+3765+2f9a457d |
| AlmaLinux:8 | python39-Cython | before 0.29.21-5.module_el8.6.0+3248+c431e88c | 0.29.21-5.module_el8.6.0+3248+c431e88c |
| AlmaLinux:8 | python39-Cython | before 0.29.21-5.module_el8.6.0+2780+a40f65e1 | 0.29.21-5.module_el8.6.0+2780+a40f65e1 |
| AlmaLinux:8 | python39-debug | before 3.9.25-2.module_el8.10.0+4083+53cad1fb | 3.9.25-2.module_el8.10.0+4083+53cad1fb |
| AlmaLinux:8 | python39-devel | before 3.9.25-2.module_el8.10.0+4083+53cad1fb | 3.9.25-2.module_el8.10.0+4083+53cad1fb |
| AlmaLinux:8 | python39-idle | before 3.9.25-2.module_el8.10.0+4083+53cad1fb | 3.9.25-2.module_el8.10.0+4083+53cad1fb |
| AlmaLinux:8 | python39-idna | before 2.10-4.module_el8.10.0+3849+a48d89aa | 2.10-4.module_el8.10.0+3849+a48d89aa |
| AlmaLinux:8 | python39-iniconfig | before 1.1.1-2.module_el8.6.0+2780+a40f65e1 | 1.1.1-2.module_el8.6.0+2780+a40f65e1 |
| AlmaLinux:8 | python39-libs | before 3.9.25-2.module_el8.10.0+4083+53cad1fb | 3.9.25-2.module_el8.10.0+4083+53cad1fb |
| AlmaLinux:8 | python39-lxml | before 4.6.5-1.module_el8.6.0+2780+a40f65e1 | 4.6.5-1.module_el8.6.0+2780+a40f65e1 |
| AlmaLinux:8 | python39-lxml | before 4.6.5-1.module_el8.6.0+3248+c431e88c | 4.6.5-1.module_el8.6.0+3248+c431e88c |
| AlmaLinux:8 | python39-mod_wsgi | before 4.7.1-7.module_el8.10.0+3989+a618fe15.1 | 4.7.1-7.module_el8.10.0+3989+a618fe15.1 |
| AlmaLinux:8 | python39-more-itertools | before 8.5.0-2.module_el8.6.0+2780+a40f65e1 | 8.5.0-2.module_el8.6.0+2780+a40f65e1 |
| AlmaLinux:8 | python39-numpy | before 1.19.4-3.module_el8.6.0+3248+c431e88c | 1.19.4-3.module_el8.6.0+3248+c431e88c |
| AlmaLinux:8 | python39-numpy | before 1.19.4-3.module_el8.6.0+2780+a40f65e1 | 1.19.4-3.module_el8.6.0+2780+a40f65e1 |
| AlmaLinux:8 | python39-numpy-doc | before 1.19.4-3.module_el8.6.0+2780+a40f65e1 | 1.19.4-3.module_el8.6.0+2780+a40f65e1 |
| AlmaLinux:8 | python39-numpy-f2py | before 1.19.4-3.module_el8.6.0+3248+c431e88c | 1.19.4-3.module_el8.6.0+3248+c431e88c |
| AlmaLinux:8 | python39-numpy-f2py | before 1.19.4-3.module_el8.6.0+2780+a40f65e1 | 1.19.4-3.module_el8.6.0+2780+a40f65e1 |
| AlmaLinux:8 | python39-packaging | before 20.4-4.module_el8.6.0+2780+a40f65e1 | 20.4-4.module_el8.6.0+2780+a40f65e1 |
+96
Same product
python software foundation: all recordsOther highest-scoring records for the same primary product.
- CVE-2026-115557Distrust compromised intermediate certificates in ssl module37Monitor
- CVE-2025-4517Arbitrary writes via tarfile realpath overflow37Monitor
- CVE-2026-19445Use-after-free of a server-side SSLContext when sni_callback switches contexts36Monitor
Published before and after this one in the same product
- ← EarlierCVE-2024-4032Jun 17, 2024 · Incorrect IPv4 and IPv6 private ranges30Monitor
- ← EarlierCVE-2024-0397Jun 17, 2024 · Memory race condition in ssl.SSLContext certificate store methods29Monitor
- Later →CVE-2024-3219Jul 29, 2024 · Pure-Python fallback of socket.socketpair() doesn’t authenticate peer connection20Monitor
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 | 3.10.0b1 | Vendor (CNA) |
| Python Software Foundation CPython | 3.9.24 | Vendor (CNA) |
| almalinux:python-unversioned-command | 3.9.25-2.el9_7 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:python3 | 3.9.25-2.el9_7 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:python3-debug | 3.9.25-2.el9_7 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:python3-devel | 3.9.25-2.el9_7 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:python3-idle | 3.9.25-2.el9_7 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:python3-libs | 3.9.25-2.el9_7 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:python3-test | 3.9.25-2.el9_7 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:python3-tkinter | 3.9.25-2.el9_7 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:python39 | 3.9.25-2.module_el8.10.0+4083+53cad1fb · AlmaLinux:8 | Package registry (OSV) |
| almalinux:python39-attrs | 20.3.0-2.module_el8.6.0+2780+a40f65e1 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:python39-Cython | 0.29.21-5.module_el8.6.0+2780+a40f65e1 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:python39-PyMySQL | 0.10.1-2.module_el8.6.0+2780+a40f65e1 · AlmaLinux:8 | Package registry (OSV) |
| debian:pypy3 | 7.3.10+dfsg-1 · Debian:12 | Package registry (OSV) |
| opensuse:python3 | 3.6.15-150300.10.72.1 · openSUSE:Leap Micro 5.5 | Package registry (OSV) |
| opensuse:python3-core | 3.6.15-150300.10.72.1 · openSUSE:Leap Micro 5.5 | Package registry (OSV) |
| opensuse:python3-documentation | 3.6.15-150300.10.72.1 · openSUSE:Leap 15.5 | Package registry (OSV) |
| opensuse:python38 | 3.8.19-7.1 · openSUSE:Tumbleweed | Package registry (OSV) |
| opensuse:python39 | 3.9.19-150300.4.49.1 · openSUSE:Leap 15.5 | Package registry (OSV) |
| opensuse:python39-core | 3.9.19-150300.4.49.1 · openSUSE:Leap 15.5 | Package registry (OSV) |
| opensuse:python39-documentation | 3.9.19-150300.4.49.1 · openSUSE:Leap 15.5 | Package registry (OSV) |
| red hat:python-unversioned-command | 0:3.9.25-2.el9_7 · Red Hat:enterprise_linux:9::appstream | Package registry (OSV) |
| red hat:python3 | 0:3.9.25-2.el9_7 · Red Hat:enterprise_linux:9::baseos | Package registry (OSV) |
| red hat:python3-debug | 0:3.9.25-2.el9_7 · Red Hat:enterprise_linux:9::crb | Package registry (OSV) |
| red hat:python3-devel | 0:3.9.25-2.el9_7 · Red Hat:enterprise_linux:9::appstream | Package registry (OSV) |
| red hat:python3-idle | 0:3.9.25-2.el9_7 · Red Hat:enterprise_linux:9::crb | Package registry (OSV) |
| red hat:python3-libs | 0:3.9.25-2.el9_7 · Red Hat:enterprise_linux:9::baseos | Package registry (OSV) |
| red hat:python3-test | 0:3.9.25-2.el9_7 · Red Hat:enterprise_linux:9::crb | Package registry (OSV) |
| red hat:python3-tkinter | 0:3.9.25-2.el9_7 · Red Hat:enterprise_linux:9::appstream | Package registry (OSV) |
+24
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.
No dated events beyond publication.
No history yet (it accumulates with the daily EPSS job).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
National notice (Türkiye Cybersecurity Directorate / USOM)
Official security notices citing this record; remediation advice is on the agency's page.
- TR-24-0818 · Jun 28, 2024(OpenSSL Güvenlik Bildirimi)
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- No account or password is required.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- low · data can be read
- Integrity
- none
- Availability
- low · the service can be disrupted
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- Low
- Integrity impact
- None
- Availability impact
- Low
Weakness class (CWE)
—
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L
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
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
Show all references (7 more)Show less
- github.com/python/cpython/commit/39258d3595300bc7b952854c915f63ae2d4b9c3e
- github.com/python/cpython/commit/a2cdbb6e8188ba9ba8b356b28d91bff60e86fe31
- github.com/python/cpython/issues/121227
- github.com/python/cpython/pull/23014
- jbp.io/2024/06/27/cve-2024-5535-openssl-memory-safety.html
- mail.python.org/archives/list/security-announce@python.org/thread/PLP2JI3PJY33YG6P5BZYSSNU66HASXBQ/
- security.netapp.com/advisory/ntap-20240726-0005/
Vendor advisories and official records. Exploit/PoC links are deliberately left out.