CVE-2025-67725

HIGHPre-NVD 7.57.5
EchelonGraph scoreMEDIUM confidence

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

This high-severity CVE scores 7.5 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.6% (45th percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.

Triggered by: Headline CVSS from a secondary CVSS source
Sources: EPSS, a secondary CVSS source
7.5EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines at low or medium mission impact and sooner than that at high (the SSVC decision on this page).
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.6%CVSS: 7.5Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

Tornado is a Python web framework and asynchronous networking library. In versions 6.5.2 and below, a single maliciously crafted HTTP request can block the server's event loop for an extended period, caused by the HTTPHeaders.add method. The function accumulates values using string concatenation when the same header name is repeated, causing a Denial of Service (DoS). Due to Python string immutability, each concatenation copies the entire string, resulting in O(n²) time complexity. The severity can vary from high if max_header_size has been increased from its default, to low if it has its default value of 64KB. This issue is fixed in version 6.5.3.

CVSS v3
7.5
EG Score
7.5HIGHmedium confidence
EG Risk
49
EG Risk 49/100

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.
Exploitation0.6% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability100% × 15%
CISA's SSVC Automatable value: yes (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Attend at high (mission-essential systems).
Exploitation none (CISA Vulnrichment) · Automatable yes (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 at low or medium mission impact and sooner than that at high.
EPSS PROB
0.6%
EPSS %ILE
45th
KEV
Not listed

SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Attend at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.

Exploitation none (CISA Vulnrichment) · Automatable yes (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)14 days if the affected system is publicly exposed; 60 days if it is not.

In CISA KEV no (CISA's KEV catalog) · Automatable yes (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 12, 2025

Last Modified

October 7, 2026

Advisory Details (2)

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

Quadratic DoS via Repeated Header Coalescing · Advisory · tornadoweb/tornado · GitHub

https://github.com/tornadoweb/tornado/security/advisories/GHSA-c98p-7wgm-6p64
GitHub commit

commit 771472cfdaee (tornadoweb/tornado)

Fix landed in tornadoweb/tornado commit 771472cfdaee — awaiting tagged release

https://github.com/tornadoweb/tornado/commit/771472cfdaeebc0d89a9cc46e249f8891a6b29cd

Vendor Advisories for CVE-2025-67725(8)

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

Patch Availability(8)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
ubuntupython3-tornado (4.2.1-1ubuntu3.1+esm2) @ xenial2026-10-07ubuntu
redhatrhoai/odh-workbench-jupyter-trustyai-cpu-py312-rhel9:17718741812026-03-04redhat
redhatpcs-0:0.10.15-4.el8_8.102026-02-10redhat
redhatpcs-0:0.11.1-10.el9_0.102026-02-10redhat
redhatpcs-0:0.10.12-6.el8_6.122026-02-10redhat
redhatpcs-0:0.10.8-1.el8_4.102026-02-10redhat
redhatrhoai/odh-workbench-jupyter-trustyai-cpu-py312-rhel9:17700554252026-02-05redhat
redhatpcs-0:0.10.18-2.el8_10.82026-01-21redhat

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)
PackageVulnerable rangeFix by version rangeDependents
python-tornado6.1.0-1, 6.1.0-1+deb11u1, 6.1.0-1+deb11u2
  • every version up to 6.1.0-1+deb11u3: fixed in 6.1.0-1+deb11u3
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
python-tornado6.2.0-3, 6.2.0-3+deb12u1, 6.2.0-3+deb12u2, 6.2.0-3+deb12u3
  • every version up to 6.2.0-3+deb12u4: fixed in 6.2.0-3+deb12u4
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
python-tornado6.4.2-3, 6.4.2-3+deb13u1
  • every version up to 6.4.2-3+deb13u2: fixed in 6.4.2-3+deb13u2
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
python-tornado6.4.2-3, 6.5.2-1, 6.5.2-2, 6.5.2-3
  • every version up to 6.5.4-0.1: fixed in 6.5.4-0.1
—
PyPI(1)
PackageVulnerable rangeFix by version rangeDependents
tornado0.2 ... 6.5b1 (78 versions)
  • every version up to 6.5.3: fixed in 6.5.3
—

Weakness Classification(1)

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

Additional Vendor Advisories

(1)

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 11× in last 7d / 32× 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 93 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. 7 repeat rows among the latest 100 are merged into the row they repeat. The 81 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-15 16:31 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  2. 2026-10-14 16:31 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  3. 2026-10-13 16:33 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  4. 2026-10-12 16:47 UTCEG score recompute
  5. 2026-10-12 16:33 UTCEPSS rescoreEPSS 0.6% · 44th percentile
  6. 2026-10-11 20:22 UTCEG score recompute
  7. 2026-10-11 18:34 UTCEG score recompute
  8. 2026-10-11 15:09 UTCEG score recompute
  9. 2026-10-11 13:47 UTCEPSS rescoreEPSS 0.6% · 44th percentile
  10. 2026-10-10 19:59 UTCEPSS rescoreEPSS 0.6% · 44th percentile
  11. 2026-10-09 20:06 UTCEPSS rescoreEPSS 0.6% · 44th percentile
  12. 2026-10-08 17:11 UTCEPSS rescoreEPSS 0.6% · 44th percentile
  13. 2026-10-07 23:47 UTCEPSS rescoreEPSS 0.6% · 44th percentile
  14. 2026-10-07 20:29 UTCEG score recompute
  15. 2026-10-07 20:29 UTCVendor advisory
  16. 2026-10-06 15:17 UTCEPSS rescoreEPSS 0.6% · 44th percentile
  17. 2026-10-05 17:42 UTCEPSS rescoreEPSS 0.6% · 44th percentile
  18. 2026-10-04 23:21 UTCEPSS rescoreEPSS 0.6% · 44th percentile
  19. 2026-10-03 18:51 UTCOSV refresh
  20. 2026-10-03 14:25 UTCEPSS rescoreEPSS 0.6% · 44th percentile
  21. 2026-10-01 19:49 UTCEPSS rescoreEPSS 0.6% · 44th percentile
  22. 2026-09-30 15:02 UTCEPSS rescoreEPSS 0.6% · 44th percentile
  23. 2026-09-29 15:20 UTCEPSS rescoreEPSS 0.6% · 44th percentile
  24. 2026-09-28 13:50 UTCEPSS rescoreEPSS 0.6% · 44th percentile
  25. 2026-09-26 15:58 UTCEPSS rescoreEPSS 0.6% · 44th percentile
Show 68 more
  1. 2026-09-24 14:02 UTCEPSS rescoreEPSS 0.6% · 44th percentile
  2. 2026-09-23 13:47 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  3. 2026-09-20 20:15 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  4. 2026-09-18 19:27 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  5. 2026-09-17 19:30 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  6. 2026-09-16 14:07 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  7. 2026-09-16 05:14 UTCEPSS rescoreEPSS 0.6% · 44th percentile
  8. 2026-09-15 03:10 UTCEPSS rescoreEPSS 0.6% · 44th percentile
  9. 2026-09-14 09:19 UTCOSV refresh
  10. 2026-09-13 16:46 UTCEPSS rescoreEPSS 0.6% · 44th percentile
  11. 2026-09-12 15:00 UTCEPSS rescoreEPSS 0.6% · 44th percentile
  12. 2026-09-11 14:52 UTCEPSS rescoreEPSS 0.6% · 44th percentile
  13. 2026-09-11 09:36 UTCEPSS rescoreEPSS 0.6% · 44th percentile
  14. 2026-09-10 09:34 UTCEPSS rescoreEPSS 0.6% · 44th percentile
  15. 2026-09-08 22:00 UTCEPSS rescoreEPSS 0.6% · 44th percentile
  16. 2026-09-07 16:00 UTCEPSS rescoreEPSS 0.6% · 44th percentile
  17. 2026-09-06 13:47 UTCEPSS rescoreEPSS 0.6% · 44th percentile
  18. 2026-09-04 05:06 UTCEPSS rescoreEPSS 0.6% · 44th percentile
  19. 2026-09-02 14:11 UTCEPSS rescoreEPSS 0.6% · 44th percentile
  20. 2026-09-01 13:53 UTCEPSS rescoreEPSS 0.6% · 44th percentile
  21. 2026-08-30 01:21 UTCEPSS rescoreEPSS 0.6% · 44th percentile
  22. 2026-08-28 21:40 UTCEPSS rescoreEPSS 0.6% · 44th percentile
  23. 2026-08-27 14:24 UTCEPSS rescoreEPSS 0.6% · 44th percentile
  24. 2026-08-26 14:45 UTCEPSS rescoreEPSS 0.6% · 44th percentile
  25. 2026-08-26 10:13 UTCOSV refresh
  26. 2026-08-25 13:48 UTCEPSS rescoreEPSS 0.6% · 44th percentile
  27. 2026-08-24 14:16 UTCEPSS rescoreEPSS 0.6% · 43rd percentile
  28. 2026-08-23 00:18 UTCEPSS rescoreEPSS 0.6% · 44th percentile
  29. 2026-08-21 23:48 UTCEPSS rescoreEPSS 0.6% · 44th percentile
  30. 2026-08-20 22:55 UTCEPSS rescoreEPSS 0.6% · 44th percentile
  31. 2026-08-19 17:03 UTCEPSS rescoreEPSS 0.6% · 44th percentile
  32. 2026-08-18 13:48 UTCEPSS rescoreEPSS 0.6% · 43rd percentile
  33. 2026-08-17 13:46 UTCEPSS rescoreEPSS 0.6% · 43rd percentile
  34. 2026-08-16 14:55 UTCEPSS rescoreEPSS 0.6% · 43rd percentile
  35. 2026-08-16 02:14 UTCEPSS rescoreEPSS 0.6% · 43rd percentile
  36. 2026-08-15 01:30 UTCEPSS rescoreEPSS 0.6% · 43rd percentile
  37. 2026-08-13 22:00 UTCEPSS rescoreEPSS 0.6% · 43rd percentile
  38. 2026-08-12 13:50 UTCEPSS rescoreEPSS 0.6% · 43rd percentile
  39. 2026-08-11 13:42 UTCEPSS rescoreEPSS 0.6% · 43rd percentile
  40. 2026-08-10 23:59 UTCEPSS rescoreEPSS 0.6% · 43rd percentile
  41. 2026-08-10 00:05 UTCEG score recompute
  42. 2026-08-10 00:05 UTCVendor advisory
  43. 2026-08-09 13:46 UTCEPSS rescoreEPSS 0.6% · 43rd percentile
  44. 2026-08-08 16:36 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  45. 2026-08-08 06:56 UTCEG score recompute
  46. 2026-08-08 06:56 UTCVendor advisory
  47. 2026-08-07 16:27 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  48. 2026-08-06 13:46 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  49. 2026-08-05 19:17 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  50. 2026-08-04 10:37 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  51. 2026-08-03 10:35 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  52. 2026-08-02 02:26 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  53. 2026-08-01 04:15 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  54. 2026-07-30 16:27 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  55. 2026-07-30 01:30 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  56. 2026-07-27 14:13 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  57. 2026-07-26 14:54 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  58. 2026-07-25 14:17 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  59. 2026-07-24 14:17 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  60. 2026-07-23 14:18 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  61. 2026-07-23 12:49 UTCOSV refresh
  62. 2026-07-23 03:02 UTCEG score recompute
  63. 2026-07-22 14:08 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  64. 2026-07-21 15:24 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  65. 2026-07-20 17:08 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  66. 2026-07-19 14:30 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  67. 2026-07-19 02:28 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  68. 2026-07-18 10:04 UTCEPSS rescoreEPSS 0.4% · 32nd percentile

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Frequently asked(5)

What is CVE-2025-67725?
CVE-2025-67725 is a high-severity vulnerability; its CVE record was published on December 12, 2025. Tornado is a Python web framework and asynchronous networking library. In versions 6.5.2 and below, a single maliciously crafted HTTP request can block the server's event loop for an extended period, caused by the HTTPHeaders.add method. The function accumulates values using string concatenation…
When was the CVE record for CVE-2025-67725 published?
The CVE record for CVE-2025-67725 was published on December 12, 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 October 7, 2026; the record at its source may have been updated since.
Is CVE-2025-67725 actively exploited?
CVE-2025-67725 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.6% probability of exploitation in the next 30 days (45th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2025-67725?
CVE-2025-67725 has a CVSS base score of 7.5 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2025-67725?
A fix for CVE-2025-67725 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2025-67725 are linked in the Vendor Advisories panel on this page.

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