CVE-2023-40217
An issue was discovered in Python before 3.8.18, 3.9.x before 3.9.18, 3.10.x before 3.10.13, and 3.11.x before 3.11.5. It primarily…
- Published
- Updated
- Reserved
- Assigned by
- mitre
Description
An issue was discovered in Python before 3.8.18, 3.9.x before 3.9.18, 3.10.x before 3.10.13, and 3.11.x before 3.11.5. It primarily affects servers (such as HTTP servers) that use TLS client authentication. If a TLS server-side socket is created, receives data into the socket buffer, and then is closed quickly, there is a brief window where the SSLSocket instance will detect the socket as "not connected" and won't initiate a handshake, but buffered data will still be readable from the socket buffer. This data will not be authenticated if the server-side TLS peer is expecting client certificate authentication, and is indistinguishable from valid TLS stream data. Data is limited in size to the amount that will fit in the buffer. (The TLS connection cannot directly be used for data exfiltration because the vulnerable code path requires that the connection be closed on initialization of the SSLSocket.)
Timeline
ID reserved
By mitre
- 15 days later
· 15 days later
Published
- 2 years later
· 2 years later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| NVDNVD · Modified | 3.1 | Medium5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N |
- EPSS (exploitation in 30 days)
- 0.80% · top 43% of all CVEs (7 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: yes · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 5.3.
Weakness
- n/a
Affected products
n/a
- affected n/a
References (7)
- https://www.python.org/dev/security/ (opens in a new tab)x_transferred
- https://mail.python.org/archives/list/security-announce%40python.org/thread/PEPLII27KYHLF4AK3ZQGKYNCRERG4YXY/ (opens in a new tab)x_transferred
- [debian-lts-announce] 20230920 [SECURITY] [DLA 3575-1] python2.7 security update (opens in a new tab)mailing-listx_transferred
- https://security.netapp.com/advisory/ntap-20231006-0014/ (opens in a new tab)x_transferred
- [debian-lts-announce] 20231011 [SECURITY] [DLA 3614-1] python3.7 security update (opens in a new tab)mailing-listx_transferred
- https://lists.debian.org/debian-lts-announce/2024/12/msg00000.html (opens in a new tab)
- https://lists.debian.org/debian-lts-announce/2024/11/msg00005.html (opens in a new tab)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2023-40217)Record last updated .