Vulnerability · Published Oct 27, 2026 · Assigned by PSF
CVE-2026-103995Lenient parsing of integers for response body and chunk framing
Low 2.0
In plain English
A low-severity security flaw in CPython from Python Software Foundation. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 30% of all known vulnerabilities).
Severity (CVSS 4.0)2.0Low
Exploit odds (30 days)0.4%top 70.1% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official description
Response body and chunk parsing would handle non-hex or negative integers incorrectly which could result in misinterpreting HTTP response contents.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu:22.04:LTS | python3.10 | no fix listed | UBUNTU-CVE-2026-103995 |
| Ubuntu:24.04:LTS | python3.12 | no fix listed | UBUNTU-CVE-2026-103995 |
| Ubuntu:26.04:LTS | python3.14 | no fix listed | UBUNTU-CVE-2026-103995 |
| Ubuntu:26.10 | python3.14 | no fix listed | UBUNTU-CVE-2026-103995 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Python Software Foundation | CPython | 0 – before 3.16.0 |
Weakness: CWE-444 · Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:P/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N