urllib3 is a user-friendly HTTP client library for Python. When using urllib3's proxy support with ProxyManager, the Proxy-Authorization header is only sent to the configured proxy, as expected. However, when sending HTTP requests *without* using urllib3's proxy support, it's possible to accidentally configure the Proxy-Authorization header even though it won't have any effect as the request is not using a forwarding proxy or a tunneling proxy. In those cases, urllib3 doesn't treat the Proxy-Authorization HTTP header as one carrying authentication material and thus doesn't strip the header on cross-origin redirects. Because this is a highly unlikely scenario, we believe the severity of this vulnerability is low for almost all users. Out of an abundance of caution urllib3 will automatically strip the Proxy-Authorization header during cross-origin redirects to avoid the small chance that users are doing this on accident. Users should use urllib3's proxy support or disable automatic redirects to achieve safe processing of the Proxy-Authorization header, but we still decided to strip the header by default in order to further protect users who aren't using the correct approach. We believe the number of usages affected by this advisory is low. It requires all of the following to be true to be exploited: 1. Setting the Proxy-Authorization header without using urllib3's built-in proxy support. 2. Not disabling HTTP redirects. 3. Either not using an HTTPS origin server or for the proxy or target origin to redirect to a malicious origin. Users are advised to update to either version 1.26.19 or version 2.2.2. Users unable to upgrade may use the Proxy-Authorization header with urllib3's ProxyManager, disable HTTP redirects using redirects=False when sending requests, or not user the Proxy-Authorization header as mitigations.
CVE-2024-37891
“—” beside the score: it is equal to NVD's CVSS score.
Score 4.4 from GitHub Security Advisory (severity: MODERATE) published 2024-06-17. NVD baseline CVSS 4.4; sources differ by 0.0.
Also known asEUVD-2024-1894 (ENISA EUVD) · GHSA-34jh-p97f-mpxf (GitHub Security Advisories)Source: ENISA EUVD
- Lower severity and no public exploit yet
A fix is available — apply it.
- CVSS v3
- 4.4
- EG Score
- 4.4MEDIUMmedium confidence
- EG Risk
- 20EG Risk 20/100
EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.
How it’s computed (value × EchelonGraph’s weight)Severity44% × 45%Impact severity (EG Severity): CVSS 4.4 of 10. Never the KEV-floored or EPSS-lifted EG Score.Exploitation1.1% × 40%FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.Automatability0% × 15%CISA's SSVC Automatable value: no (Vulnrichment).SSVC (CISA's decision table, applied by EchelonGraph): Track at every mission impact level.Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.Action: A fix is available. Apply it within your standard update timelines. - EPSS PROB
- 1.1%
- EPSS %ILE
- 66th
- KEV
- Not listed
What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)
The EG score (4.4): severity, escalated by confirmed exploitation. This CVE's 4.4 is its impact severity (EG Severity), not escalated.
- EG Severity
- 4.4 MEDIUMCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
- EG Likelihood
- 1.1% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-31). FIRST's exploitation probability, not an EchelonGraph model.
- Confirmed exploitation
- None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
- EG Priority
- SSVC Track at medium mission impactTrack at every mission impact level.CISA BOD 26-04: 60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.Each input and its source, and whom BOD 26-04 binds: the SSVC and BOD 26-04 blocks below.
SSVC (CISA's decision table, applied by EchelonGraph)Track at every mission impact level.
A fix is available. Apply it within your standard update timelines.
Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table
BOD 26-04 (CISA's remediation timeline, Table 1)60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.
The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it
Published
June 17, 2024
Last Modified
January 6, 2026
References (5)
- security-advisories@github · CVE Programhttps://github.com/urllib3/urllib3/commit/accff72ecc2f6cf5a76d9570198a93ac7c90270ePatch
- security-advisories@github · CVE Programhttps://github.com/urllib3/urllib3/security/advisories/GHSA-34jh-p97f-mpxfVendor Advisory · Mitigation
- CVE Programhttps://lists.debian.org/debian-lts-announce/2024/12/msg00020.htmlMailing List · Third Party Advisory
- CVE Programhttps://security.netapp.com/advisory/ntap-20240822-0003/Third Party Advisory
- CVE Programhttps://www.vicarius.io/vsociety/posts/proxy-authorization-header-handling-vulnerability-in-urllib3-cve-2024-37891Exploit · Third Party Advisory · Mitigation
Vendor Advisories for CVE-2024-37891(20)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
- RHSA-2024:9985Red Hat Product SecurityMedium
Red Hat Security Advisory: RHOSP 17.1.4 (python-urllib3) security update
- RHSA-2024:9922Red Hat Product SecurityMedium
Red Hat Security Advisory: python3.11-urllib3 security update
- RHSA-2024:9923Red Hat Product SecurityMedium
Red Hat Security Advisory: python3.12-urllib3 security update
- RHSA-2024:9458Red Hat Product SecurityMedium
Red Hat Security Advisory: python3.11-urllib3 security update
- RHSA-2024:9457Red Hat Product SecurityMedium
Red Hat Security Advisory: python3.12-urllib3 security update
- RHSA-2024:8906Red Hat Product SecurityCritical
Red Hat Security Advisory: Satellite 6.16.0 release
- RHSA-2024:8842Red Hat Product SecurityMedium
Red Hat Security Advisory: python3.12-urllib3 security update
- RHSA-2024:8843Red Hat Product SecurityMedium
Red Hat Security Advisory: python3.11-urllib3 security update
- +12 more
Patch Availability(32)
Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.
Affected Packages
(5 across 5 ecosystems)
Debian:11(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| python-urllib3 | 1.26.5-1~exp1 |
| — |
Debian:12(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| python-urllib3 | 1.26.12-1 |
| — |
Debian:13(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| python-urllib3 | — |
| — |
Debian:14(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| python-urllib3 | — |
| — |
PyPI(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| urllib3 | 0.2 ... 2.2.1 (92 versions) |
| — |
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Additional Vendor Advisories
(11)
Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.
- Microsoft MSRCCVE-2024-378912024-07-10
Proxy-Authorization request header isn't stripped during cross-origin redirects in urllib3
- Red HatRHSA-2024:4422MODERATE2024-06-17
RHSA-2024:4422 — Moderate
- Red HatRHSA-2024:4730MODERATE2024-06-17
RHSA-2024:4730 — Moderate
- Red HatRHSA-2024:4744MODERATE2024-06-17
RHSA-2024:4744 — Moderate
- Red HatRHSA-2024:4746MODERATE2024-06-17
RHSA-2024:4746 — Moderate
- Red HatRHSA-2024:5041MODERATE2024-06-17
RHSA-2024:5041 — Moderate
- Red HatRHSA-2024:5258MODERATE2024-06-17
RHSA-2024:5258 — Moderate
- Red HatRHSA-2024:5309MODERATE2024-06-17
RHSA-2024:5309 — Moderate
- Red HatRHSA-2024:5526MODERATE2024-06-17
RHSA-2024:5526 — Moderate
- Red HatRHSA-2024:5627MODERATE2024-06-17
RHSA-2024:5627 — Moderate
- Red HatRHSA-2024:6162MODERATE2024-06-17
RHSA-2024:6162 — Moderate
Data Freshness Timeline
(refreshed 9× in last 7d / 40× in last 30d)
Each row is a time one of our pipelines fetched, updated or re-scored this CVE. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.
Showing the most recent 96 of 213 refreshes on record for this CVE.
A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. 4 repeat rows among the latest 100 are merged into the row they repeat. The 117 oldest rows on record are not shown and were not checked, so the counts can still include repeats.
- 2026-11-02 16:41 UTCEPSS rescoreEPSS 1.1% · 66th percentile
- 2026-11-01 16:31 UTCEPSS rescoreEPSS 1.1% · 66th percentile
- 2026-11-01 08:13 UTCGHSA enrichmentGHSA-34jh-p97f-mpxf · GitHub severity MODERATE · GitHub CVSS 4.4
- 2026-11-01 08:13 UTCEG score recompute
- 2026-10-31 16:30 UTCEPSS rescoreEPSS 1.1% · 66th percentile
- 2026-10-30 16:32 UTCEPSS rescoreEPSS 1.1% · 66th percentile
- 2026-10-29 16:30 UTCEPSS rescoreEPSS 1.1% · 66th percentile
- 2026-10-28 16:29 UTCEPSS rescoreEPSS 1.1% · 66th percentile
- 2026-10-27 16:29 UTCEPSS rescoreEPSS 1.1% · 66th percentile
- 2026-10-26 16:29 UTCEPSS rescoreEPSS 1.1% · 66th percentile
- 2026-10-25 17:07 UTCEG score recompute
- 2026-10-25 16:30 UTCEPSS rescoreEPSS 1.1% · 66th percentile
- 2026-10-24 16:30 UTCEPSS rescoreEPSS 1.1% · 66th percentile
- 2026-10-24 06:14 UTCEG score recompute
- 2026-10-24 06:14 UTCVendor advisory
- 2026-10-23 16:29 UTCEPSS rescoreEPSS 1.1% · 66th percentile
- 2026-10-22 16:31 UTCEPSS rescoreEPSS 1.1% · 66th percentile
- 2026-10-21 16:29 UTCEPSS rescoreEPSS 1.1% · 66th percentile
- 2026-10-20 16:30 UTCEPSS rescoreEPSS 1.1% · 66th percentile
- 2026-10-19 16:29 UTCEPSS rescoreEPSS 1.1% · 66th percentile
- 2026-10-18 16:30 UTCEPSS rescoreEPSS 1.1% · 66th percentile
- 2026-10-18 07:11 UTCEG score recompute
- 2026-10-17 16:31 UTCEPSS rescoreEPSS 1.1% · 66th percentile
- 2026-10-16 16:36 UTCEPSS rescoreEPSS 1.1% · 66th percentile
- 2026-10-15 16:30 UTCEPSS rescoreEPSS 1.1% · 66th percentile
Show 71 moreShow fewer
- 2026-10-14 16:30 UTCEPSS rescoreEPSS 1.1% · 65th percentile
- 2026-10-13 16:30 UTCEPSS rescoreEPSS 1.1% · 65th percentile
- 2026-10-12 17:51 UTCEG score recompute
- 2026-10-12 16:31 UTCEPSS rescoreEPSS 1.1% · 65th percentile
- 2026-10-11 21:16 UTCEG score recompute
- 2026-10-11 16:08 UTCEG score recompute
- 2026-10-11 13:46 UTCEPSS rescoreEPSS 1.1% · 65th percentile
- 2026-10-10 19:58 UTCEPSS rescoreEPSS 1.1% · 65th percentile
- 2026-10-10 16:25 UTCOSV refresh
- 2026-10-09 20:05 UTCEPSS rescoreEPSS 1.1% · 65th percentile
- 2026-10-08 17:07 UTCEPSS rescoreEPSS 1.1% · 65th percentile
- 2026-10-07 23:46 UTCEPSS rescoreEPSS 1.1% · 65th percentile
- 2026-10-06 15:15 UTCEPSS rescoreEPSS 1.1% · 65th percentile
- 2026-10-05 17:41 UTCEPSS rescoreEPSS 1.1% · 65th percentile
- 2026-10-04 23:20 UTCEPSS rescoreEPSS 1.1% · 65th percentile
- 2026-10-03 14:24 UTCEPSS rescoreEPSS 1.1% · 65th percentile
- 2026-10-01 19:48 UTCEPSS rescoreEPSS 1.1% · 65th percentile
- 2026-09-30 19:47 UTCEG score recompute
- 2026-09-30 15:01 UTCEPSS rescoreEPSS 1.1% · 65th percentile
- 2026-09-29 15:17 UTCEPSS rescoreEPSS 1.1% · 65th percentile
- 2026-09-28 13:49 UTCEPSS rescoreEPSS 1.1% · 65th percentile
- 2026-09-27 13:44 UTCEPSS rescoreEPSS 1.1% · 65th percentile
- 2026-09-26 15:57 UTCEPSS rescoreEPSS 1.1% · 65th percentile
- 2026-09-26 00:23 UTCEPSS rescoreEPSS 1.1% · 65th percentile
- 2026-09-24 14:01 UTCEPSS rescoreEPSS 1.1% · 65th percentile
- 2026-09-23 13:46 UTCEPSS rescoreEPSS 1.1% · 65th percentile
- 2026-09-22 14:46 UTCEPSS rescoreEPSS 1.1% · 65th percentile
- 2026-09-21 20:32 UTCEPSS rescoreEPSS 1.1% · 64th percentile
- 2026-09-21 03:19 UTCOSV refresh
- 2026-09-20 20:14 UTCEPSS rescoreEPSS 1.1% · 65th percentile
- 2026-09-19 15:40 UTCEPSS rescoreEPSS 1.1% · 65th percentile
- 2026-09-18 19:26 UTCEPSS rescoreEPSS 1.1% · 65th percentile
- 2026-09-16 14:06 UTCEPSS rescoreEPSS 1.1% · 65th percentile
- 2026-09-15 03:08 UTCEPSS rescoreEPSS 1.1% · 64th percentile
- 2026-09-13 16:45 UTCEPSS rescoreEPSS 1.1% · 64th percentile
- 2026-09-12 14:59 UTCEPSS rescoreEPSS 1.1% · 64th percentile
- 2026-09-11 14:51 UTCEPSS rescoreEPSS 1.1% · 64th percentile
- 2026-09-11 09:35 UTCEPSS rescoreEPSS 1.1% · 64th percentile
- 2026-09-08 21:58 UTCEPSS rescoreEPSS 1.1% · 64th percentile
- 2026-09-07 15:59 UTCEPSS rescoreEPSS 1.1% · 64th percentile
- 2026-09-06 13:46 UTCEPSS rescoreEPSS 1.1% · 64th percentile
- 2026-09-05 15:26 UTCEPSS rescoreEPSS 1.1% · 64th percentile
- 2026-09-04 13:59 UTCEPSS rescoreEPSS 1.1% · 64th percentile
- 2026-09-04 05:05 UTCEPSS rescoreEPSS 1.1% · 64th percentile
- 2026-09-02 14:10 UTCEPSS rescoreEPSS 1.1% · 64th percentile
- 2026-09-02 01:12 UTCOSV refresh
- 2026-09-01 13:52 UTCEPSS rescoreEPSS 1.1% · 64th percentile
- 2026-09-01 04:37 UTCEPSS rescoreEPSS 1.1% · 64th percentile
- 2026-08-30 19:15 UTCEPSS rescoreEPSS 1.1% · 64th percentile
- 2026-08-30 01:20 UTCEPSS rescoreEPSS 1.1% · 63rd percentile
- 2026-08-28 21:39 UTCEPSS rescoreEPSS 1.1% · 63rd percentile
- 2026-08-27 14:23 UTCEPSS rescoreEPSS 1.1% · 64th percentile
- 2026-08-26 14:44 UTCEPSS rescoreEPSS 1.1% · 64th percentile
- 2026-08-25 13:47 UTCEPSS rescoreEPSS 1.1% · 64th percentile
- 2026-08-24 14:15 UTCEPSS rescoreEPSS 1.1% · 64th percentile
- 2026-08-23 00:18 UTCEPSS rescoreEPSS 1.1% · 64th percentile
- 2026-08-21 23:47 UTCEPSS rescoreEPSS 1.1% · 64th percentile
- 2026-08-20 22:53 UTCEPSS rescoreEPSS 1.1% · 64th percentile
- 2026-08-19 17:02 UTCEPSS rescoreEPSS 1.1% · 64th percentile
- 2026-08-18 13:46 UTCEPSS rescoreEPSS 1.1% · 63rd percentile
- 2026-08-17 13:45 UTCEPSS rescoreEPSS 1.1% · 63rd percentile
- 2026-08-16 14:54 UTCEPSS rescoreEPSS 1.1% · 63rd percentile
- 2026-08-16 04:13 UTCOSV refresh
- 2026-08-16 02:13 UTCEPSS rescoreEPSS 1.1% · 63rd percentile
- 2026-08-15 01:28 UTCEPSS rescoreEPSS 1.1% · 63rd percentile
- 2026-08-13 21:59 UTCEPSS rescoreEPSS 1.1% · 63rd percentile
- 2026-08-12 13:49 UTCEPSS rescoreEPSS 1.1% · 63rd percentile
- 2026-08-11 13:40 UTCEPSS rescoreEPSS 1.1% · 63rd percentile
- 2026-08-10 23:58 UTCEPSS rescoreEPSS 1.1% · 63rd percentile
- 2026-08-09 13:45 UTCEPSS rescoreEPSS 1.1% · 63rd percentile
- 2026-08-08 16:35 UTCEPSS rescoreEPSS 1.1% · 63rd percentile
Related CVEs(same product + same vendor + same CWE)
Same product
10 shownDebian:11:python-urllib3
Same vendor
10 shownredhat:RHBA-2024:7523 · redhat:RHSA-2024:6309 · redhat:RHSA-2024:8906
Frequently asked(5)
What is CVE-2024-37891?
When was the CVE record for CVE-2024-37891 published?
Is CVE-2024-37891 actively exploited?
What is the CVSS score of CVE-2024-37891?
How do I remediate CVE-2024-37891?
Dependency Blast Radius
See which npm, PyPI, Go, and Maven packages are affected by CVE-2024-37891
Is Your Infrastructure Affected by CVE-2024-37891?
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