Security readout for executives and security teams
Plain-English summary
CVE-2026-44431 affects urllib3, a common Python HTTP library. In specific proxied redirect scenarios, sensitive headers can be forwarded to a different origin. This can expose credentials or tokens carried in headers. The issue affects urllib3 versions 1.23 through before 2.7.0 and is fixed in 2.7.0.
Executive priority
Treat as high priority for systems that send credentials or tokens through Python HTTP clients. Patch affected urllib3 installations promptly, but do not assume broad exposure without confirming the specific low-level API pattern.
Technical view
When using urllib3 ProxyManager.connection_from_url().urlopen(...) with assert_same_host=False, cross-origin redirects may still forward sensitive headers. The vulnerability is classified as CWE-200 information exposure. CVSS v4.0 is 8.2 high, with network attack vector, high confidentiality impact, and required attack conditions.
Likely exposure
Exposure is most likely in Python applications or services that use urllib3 directly, especially low-level ProxyManager usage with redirects and assert_same_host=False. Applications relying only on higher-level wrappers may not be affected unless they invoke this vulnerable path.
Exploitation context
The source bundle does not indicate active exploitation, and the CVE is not listed as KEV. Exploitation would require conditions where a proxied request follows a cross-origin redirect while carrying sensitive headers through the affected low-level API path.
Researcher notes
Key condition is proxied, low-level urllib3 redirect handling with assert_same_host=False. The impact is header disclosure across origins, not integrity or availability compromise. Avoid assuming exploitability in applications that do not use this call path.
Mitigation direction
- Upgrade urllib3 to version 2.7.0 or later.
- Prioritize internet-facing services and systems handling authorization headers, cookies, or tokens.
- Review vendor or distribution guidance, including Debian LTS advisories where applicable.
- Reduce unnecessary low-level redirect handling across origins until patched.
Validation and detection
- Inventory Python environments and dependency manifests for urllib3 versions 1.23 to before 2.7.0.
- Identify code using ProxyManager.connection_from_url().urlopen with assert_same_host=False.
- Review whether affected calls can follow redirects while sending sensitive headers.
- Confirm deployed runtime packages match the remediated urllib3 version.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-200: Information exposure and cloud metadata lookup
Information exposure and SSRF weaknesses can make discovery, cloud metadata, and credential material review relevant. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2026-44431 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- High
- CVSS
- 8.2 (4.0)
- Known Exploited
- No
- Published
Vector: CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
SSVC decision data
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N——GitHub_MVulnerability scoring details
Base CVSS 4.0 score
8.2HighVector: CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- CVE publishedCVE Program
The CVE record was published.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/urllib3/urllib3/security/advisories/GHSA-qccp-gfcp-xxvcCVE reference, GitHub_M · x_refsource_CONFIRM
- https://lists.debian.org/debian-lts-announce/2026/06/msg00040.htmlCVE reference, CVE
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Exposure of Sensitive Information to an Unauthorized Actor
Exposure of Sensitive Information to an Unauthorized Actor represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.