CVE-2025-66471

HIGHNVD 7.57.5
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to NVD's CVSS score.

This high-severity CVE scores 7.5 under NVD CVSS v3. EPSS exploit probability: 0.7% (51st percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.

Triggered by: Headline CVSS from NVD CVSS v3
Sources: EPSS, NVD CVSS v3
7.5EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines (the SSVC decision on this page).
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.7%CVSS: 7.5Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

urllib3 is a user-friendly HTTP client library for Python. Starting in version 1.0 and prior to 2.6.0, the Streaming API improperly handles highly compressed data. urllib3's streaming API is designed for the efficient handling of large HTTP responses by reading the content in chunks, rather than loading the entire response body into memory at once. When streaming a compressed response, urllib3 can perform decoding or decompression based on the HTTP Content-Encoding header (e.g., gzip, deflate, br, or zstd). The library must read compressed data from the network and decompress it until the requested chunk size is met. Any resulting decompressed data that exceeds the requested amount is held in an internal buffer for the next read operation. The decompression logic could cause urllib3 to fully decode a small amount of highly compressed data in a single operation. This can result in excessive resource consumption (high CPU usage and massive memory allocation for the decompressed data.

CVSS v3
7.5
EG Score
7.5HIGHmedium confidence
EG Risk
34
EG Risk 34/100

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed (value × EchelonGraph’s weight)
Severity75% × 45%
The EG Score, 7.5 of 10.
Exploitation0.7% × 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
0.7%
EPSS %ILE
51st
KEV
Not listed

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.

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

December 5, 2025

Last Modified

September 25, 2026

Advisory Details (2)

Auto-updated Aug 8, 2026
Patch available. Sources: github_commit, github.
GitHub advisoryMentions a patch (unverified)

Streaming API improperly handles highly compressed data · Advisory · urllib3/urllib3 · GitHub

https://github.com/urllib3/urllib3/security/advisories/GHSA-2xpw-w6gg-jr37
GitHub commit Patch Available

commit c19571de34c4 (urllib3/urllib3)

Patch available: urllib3/urllib3 2.6.0 (contains commit c19571de34c4)

https://github.com/urllib3/urllib3/commit/c19571de34c47de3a766541b041637ba5f716ed7

Vendor Advisories for CVE-2025-66471(20)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(30)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
redhatrhaiis/model-opt-cuda-rhel9:17877721572026-08-31redhat
redhatrhoai/odh-kserve-storage-initializer-rhel9:17870734792026-08-27redhat
redhatsatellite/iop-vulnerability-engine-rhel9:17845541232026-08-06redhat
redhatsatellite/iop-advisor-engine-rhel9:17848344022026-07-23redhat
redhatrhmtc/openshift-migration-velero-plugin-for-mtc-rhel8:17839142552026-07-20redhat
redhatsatellite/iop-host-inventory-frontend-rhel9:17822530702026-07-01redhat
redhatopenshift/mirror-registry-rhel8:17821770122026-06-23redhat
redhatpython-urllib3-0:1.26.5-3.el8ost.32026-06-22redhat
redhatrhoai/odh-vllm-cpu-rhel9:17782643632026-05-20redhat
redhatsatellite/iop-puptoo-rhel9:17767968292026-05-07redhat
redhatpython-urllib3-0:1.10.2-3.el6_10.12026-04-29redhat
redhatrhoai/odh-vllm-cpu-rhel9:17762590632026-04-23redhat
redhatpython-urllib3-0:1.10.2-7.el7_9.12026-04-20redhat
redhatsatellite/iop-insights-engine-rhel9:17738379612026-03-31redhat
redhatopenshift-builds/openshift-builds-shared-resource-rhel9:17739315902026-03-30redhat
redhatopenshift-builds/openshift-builds-shared-resource-rhel9:17739319942026-03-24redhat
redhatrhtas/tuffer-rhel9:17733073092026-03-23redhat
redhatadvanced-cluster-security/rhacs-scanner-v4-db-rhel8:17732358802026-03-12redhat
redhatadvanced-cluster-security/rhacs-collector-rhel8:17714013142026-03-12redhat
redhatrhtas/model-transparency-rhel9:17726146352026-03-11redhat
redhatquay/quay-rhel8:17730888622026-03-10redhat
redhatquay/quay-rhel8:17730976212026-03-10redhat
redhatansible-automation-platform-26/hub-rhel9-operator:17723823252026-03-06redhat
redhatopenshift-gitops-1/console-plugin-rhel8:17721959952026-03-05redhat
redhatopenshift-gitops-1/console-plugin-rhel8:17724388222026-03-05redhat
redhatrhoai/odh-workbench-jupyter-trustyai-cpu-py312-rhel9:17718741812026-03-04redhat
redhatrhoai/odh-vllm-gaudi-rhel9:17720932782026-03-04redhat
redhatrhaiis/vllm-cuda-rhel9:17721605932026-02-27redhat
redhatrhaiis/vllm-rocm-rhel9:17721606252026-02-27redhat
redhatrhceph/rhceph-9-rhel9:17718160282026-02-26redhat

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

(6 across 6 ecosystems)
Alpine:v3.23(1)
PackageVulnerable rangeFix by version rangeDependents
py3-urllib3—
  • every version up to 2.6.3-r0: fixed in 2.6.3-r0
—
Debian:11(1)
PackageVulnerable rangeFix by version rangeDependents
python-urllib31.26.12-1 ... 2.7.0-3 (29 versions)
  • every version on: no fix on record
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
python-urllib31.26.12-1 ... 2.8.0-1 (27 versions)
  • every version on: no fix on record
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
python-urllib32.3.0-3 ... 2.8.0-1 (12 versions)
  • every version on: no fix on record
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
python-urllib32.3.0-3, 2.5.0-1, 2.5.0-1.1, 2.5.0-2
  • every version up to 2.6.3-1: fixed in 2.6.3-1
—
PyPI(1)
PackageVulnerable rangeFix by version rangeDependents
urllib31.0 ... 2.5.0 (98 versions)
  • 1.0 up to 2.6.0: fixed in 2.6.0
—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Additional Vendor Advisories

(22)

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.

Data Freshness Timeline

(refreshed 12× in last 7d / 31× 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 91 of 174 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. 9 repeat rows among the latest 100 are merged into the row they repeat. The 83 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-14 16:31 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  2. 2026-10-13 16:33 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  3. 2026-10-12 16:48 UTCEG score recompute
  4. 2026-10-12 16:33 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  5. 2026-10-11 20:23 UTCEG score recompute
  6. 2026-10-11 18:35 UTCEG score recompute
  7. 2026-10-11 15:09 UTCEG score recompute
  8. 2026-10-11 13:47 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  9. 2026-10-10 19:59 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  10. 2026-10-09 20:06 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  11. 2026-10-08 17:10 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  12. 2026-10-07 23:47 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  13. 2026-10-06 15:17 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  14. 2026-10-05 17:42 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  15. 2026-10-04 23:21 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  16. 2026-10-03 14:25 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  17. 2026-10-01 19:49 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  18. 2026-09-30 15:02 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  19. 2026-09-29 15:20 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  20. 2026-09-28 13:50 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  21. 2026-09-26 15:58 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  22. 2026-09-25 23:28 UTCEG score recompute
  23. 2026-09-25 23:28 UTCVendor advisory
  24. 2026-09-24 14:02 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  25. 2026-09-23 13:47 UTCEPSS rescoreEPSS 0.7% · 51st percentile
Show 66 more
  1. 2026-09-20 20:15 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  2. 2026-09-19 15:42 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  3. 2026-09-18 19:27 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  4. 2026-09-17 19:30 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  5. 2026-09-16 14:07 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  6. 2026-09-15 03:10 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  7. 2026-09-13 16:46 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  8. 2026-09-12 15:00 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  9. 2026-09-12 07:40 UTCOSV refresh
  10. 2026-09-11 14:52 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  11. 2026-09-11 09:36 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  12. 2026-09-10 09:34 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  13. 2026-09-08 22:00 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  14. 2026-09-07 16:00 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  15. 2026-09-06 13:47 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  16. 2026-09-04 05:06 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  17. 2026-09-02 14:11 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  18. 2026-09-01 13:53 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  19. 2026-08-30 19:16 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  20. 2026-08-30 01:21 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  21. 2026-08-28 21:40 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  22. 2026-08-27 14:24 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  23. 2026-08-26 14:45 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  24. 2026-08-25 13:48 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  25. 2026-08-24 14:16 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  26. 2026-08-24 13:02 UTCOSV refresh
  27. 2026-08-23 00:18 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  28. 2026-08-21 23:48 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  29. 2026-08-20 22:55 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  30. 2026-08-19 17:03 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  31. 2026-08-18 13:47 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  32. 2026-08-17 13:46 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  33. 2026-08-16 14:55 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  34. 2026-08-16 02:13 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  35. 2026-08-15 01:29 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  36. 2026-08-13 21:59 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  37. 2026-08-12 13:50 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  38. 2026-08-11 13:42 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  39. 2026-08-10 23:59 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  40. 2026-08-09 13:46 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  41. 2026-08-08 16:36 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  42. 2026-08-08 08:30 UTCEG score recompute
  43. 2026-08-08 08:30 UTCVendor advisory
  44. 2026-08-07 16:26 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  45. 2026-08-06 13:46 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  46. 2026-08-05 19:17 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  47. 2026-08-04 15:09 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  48. 2026-08-04 10:37 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  49. 2026-08-03 10:35 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  50. 2026-08-02 02:26 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  51. 2026-08-01 04:15 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  52. 2026-07-30 16:27 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  53. 2026-07-30 01:30 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  54. 2026-07-28 15:35 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  55. 2026-07-27 14:12 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  56. 2026-07-26 14:54 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  57. 2026-07-25 14:17 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  58. 2026-07-24 14:17 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  59. 2026-07-23 14:18 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  60. 2026-07-23 13:49 UTCOSV refresh
  61. 2026-07-23 03:01 UTCEG score recompute
  62. 2026-07-22 14:08 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  63. 2026-07-21 15:24 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  64. 2026-07-20 17:08 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  65. 2026-07-19 14:30 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  66. 2026-07-19 02:28 UTCEPSS rescoreEPSS 0.6% · 46th percentile

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Frequently asked(5)

What is CVE-2025-66471?
CVE-2025-66471 is a high-severity vulnerability; its CVE record was published on December 5, 2025. urllib3 is a user-friendly HTTP client library for Python. Starting in version 1.0 and prior to 2.6.0, the Streaming API improperly handles highly compressed data. urllib3's streaming API is designed for the efficient handling of large HTTP responses by reading the content in chunks, rather than…
When was the CVE record for CVE-2025-66471 published?
The CVE record for CVE-2025-66471 was published on December 5, 2025. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of September 25, 2026; the record at its source may have been updated since.
Is CVE-2025-66471 actively exploited?
CVE-2025-66471 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.7% probability of exploitation in the next 30 days (51st percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2025-66471?
CVE-2025-66471 has a CVSS v3 base score of 7.5 (NVD).
How do I remediate CVE-2025-66471?
A fix for CVE-2025-66471 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2025-66471 are linked in the Vendor Advisories panel on this page.

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