CVE-2026-97688

MEDIUMNVD 5.35.3
EchelonGraph scoreMEDIUM confidence

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

This medium-severity CVE scores 5.3 under NVD CVSS v3. EPSS exploit probability: 0.3% (21st 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
Trending — 4 sources updated this week

Also known asEUVD-2026-89007 (ENISA EUVD) · GHSA-gh4c-6fx4-qh6g (GitHub Security Advisories)Source: ENISA EUVD

5.3EG
EchelonGraph verdictMonitorRemediate within your standard update timelines at low or medium mission impact and sooner than that at high (the SSVC decision on this page).
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.3%CVSS: 5.3Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

urllib3 is an HTTP client library for Python. From 2.6.2 until 2.8.0, HTTPResponse.stream and HTTPResponse.read_chunked can enter an infinite loop because the Deflate decoder retains trailing bytes as unconsumed input after reaching end-of-stream and repeatedly decodes them without progress. The issue occurs when an untrusted server sends a chunked Deflate response whose decoded body exceeds a positive finite chunk size and whose encoded body has trailing bytes, specifically a response with Transfer-Encoding: chunked and Content-Encoding: deflate, content decoding enabled, and the positive finite amt=N streaming chunk size. The attack mechanism is that a malicious server returns a compressed chunked response with trailing bytes after the Deflate stream. The impact is excessive CPU usage and a request that does not complete, and network read timeouts do not interrupt the loop because no further socket read occurs. This issue is fixed in version 2.8.0.

CVSS v3
5.3
EG Score
5.3MEDIUMmedium confidence
EG Risk
39
EG Risk 39/100

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)
Severity53% × 45%
Impact severity (EG Severity): CVSS 5.3 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0.3% × 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
0.3%
EPSS %ILE
21st
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 (5.3): severity, escalated by confirmed exploitation. This CVE's 5.3 is its impact severity (EG Severity), not escalated.

EG Severity
5.3 MEDIUMCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.NVD CVSS v3 · CVSS v3.0 or v3.1
EG Likelihood
0.3% 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 low or medium mission impact; Attend at high (mission-essential systems).CISA BOD 26-04: 14 days if the affected system is publicly exposed; 60 days 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 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.

The score's inputs: 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

September 29, 2026

Last Modified

October 13, 2026

Advisory Details (3)

Auto-updated Sep 29, 2026
Patch available. Sources: github, github_commit, github_release.
GitHub release Patch Available

2.8.0

Patch available: urllib3/urllib3 2.8.0

https://github.com/urllib3/urllib3/releases/tag/2.8.0
GitHub commit Patch Available

commit ea2ad7b21a80 (urllib3/urllib3)

Patch available: urllib3/urllib3 2.8.0 (contains commit ea2ad7b21a80)

https://github.com/urllib3/urllib3/commit/ea2ad7b21a80da3632f80016526a18864586077f
GitHub advisoryMentions a patch (unverified)

Chunked Deflate streaming can enter an infinite loop · Advisory · urllib3/urllib3 · GitHub

https://github.com/urllib3/urllib3/security/advisories/GHSA-gh4c-6fx4-qh6g

Patch Availability(13)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
ubuntupython3-urllib3 (2.6.3-1ubuntu1.2) @ resolute2026-10-29ubuntu
redhatrhaii/model-opt-cuda-rhel9:17918571102026-10-14redhat
redhatrhaii/vllm-spyre-rhel9:17918585922026-10-14redhat
redhatrhaii/vllm-cpu-rhel9:17918573012026-10-14redhat
redhatrhaii/vllm-rocm-rhel9:17918567252026-10-14redhat
redhatrhaii/vllm-cuda-rhel9:17918571832026-10-14redhat
redhatrhaii/vllm-spyre-rhel9:17918183572026-10-13redhat
redhatrhaii/vllm-rocm-rhel9:17914258692026-10-13redhat
redhatrhaii/vllm-gaudi-rhel9:17914271822026-10-13redhat
redhatrhaii/vllm-cuda-rhel9:17914736312026-10-13redhat
redhatrhaii/vllm-cpu-rhel9:17914736142026-10-13redhat
redhatpython-urllib3-main-2.8.0-1.hum12026-09-21redhat
pipurllib3 @ 2.8.0 (fixes >= 2.6.2, < 2.8.0)—ghsa

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

(2 across 2 ecosystems)
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
python-urllib32.3.0-3 ... 2.7.0-3 (9 versions)
  • every version up to 2.8.0-1: fixed in 2.8.0-1
—
PyPI(1)
PackageVulnerable rangeFix by version rangeDependents
urllib32.6.2, 2.6.3, 2.7.0
  • 2.6.2 up to 2.8.0: fixed in 2.8.0
—

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 10× in last 7d / 63× 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.

  1. 2026-11-01 07:37 UTCGHSA enrichmentGHSA-gh4c-6fx4-qh6g · GitHub severity MODERATE
  2. 2026-11-01 07:37 UTCEG score recompute
  3. 2026-10-31 16:33 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  4. 2026-10-30 16:35 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  5. 2026-10-29 17:10 UTCEG score recompute
  6. 2026-10-29 17:10 UTCVendor advisory
  7. 2026-10-29 16:34 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  8. 2026-10-28 16:33 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  9. 2026-10-27 16:33 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  10. 2026-10-26 16:33 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  11. 2026-10-25 16:34 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  12. 2026-10-25 13:47 UTCEG score recompute
  13. 2026-10-24 16:34 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  14. 2026-10-23 16:33 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  15. 2026-10-22 16:35 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  16. 2026-10-22 12:00 UTCEG score recompute
  17. 2026-10-22 12:00 UTCVendor advisory
  18. 2026-10-21 16:34 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  19. 2026-10-20 16:34 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  20. 2026-10-19 16:33 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  21. 2026-10-18 16:33 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  22. 2026-10-18 02:56 UTCEG score recompute
  23. 2026-10-17 16:35 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  24. 2026-10-16 16:45 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  25. 2026-10-15 16:33 UTCEPSS rescoreEPSS 0.3% · 20th percentile
Show 51 more
  1. 2026-10-14 16:34 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  2. 2026-10-13 20:36 UTCEG score recompute▼ 1.60
  3. 2026-10-13 20:36 UTCVendor advisory
  4. 2026-10-13 20:24 UTCNVD updateCVSS v3 → 5.3
  5. 2026-10-13 16:35 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  6. 2026-10-12 16:35 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  7. 2026-10-12 14:39 UTCEG score recompute
  8. 2026-10-11 19:10 UTCEG score recompute
  9. 2026-10-11 18:18 UTCVendor advisory
  10. 2026-10-11 16:26 UTCEG score recompute
  11. 2026-10-11 13:50 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  12. 2026-10-11 13:38 UTCEG score recompute
  13. 2026-10-10 20:26 UTCEG score recompute
  14. 2026-10-10 20:26 UTCVendor advisory
  15. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  16. 2026-10-09 22:30 UTCEG score recompute
  17. 2026-10-09 22:30 UTCVendor advisory
  18. 2026-10-09 20:08 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  19. 2026-10-09 00:38 UTCEG score recompute
  20. 2026-10-09 00:38 UTCVendor advisory
  21. 2026-10-08 17:14 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  22. 2026-10-08 02:47 UTCEG score recompute
  23. 2026-10-08 02:47 UTCVendor advisory
  24. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  25. 2026-10-07 04:56 UTCEG score recompute
  26. 2026-10-07 04:56 UTCVendor advisory
  27. 2026-10-06 15:19 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  28. 2026-10-06 07:04 UTCEG score recompute
  29. 2026-10-06 07:04 UTCVendor advisory
  30. 2026-10-05 17:44 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  31. 2026-10-05 09:12 UTCEG score recompute
  32. 2026-10-05 09:12 UTCVendor advisory
  33. 2026-10-04 23:23 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  34. 2026-10-04 11:16 UTCEG score recompute
  35. 2026-10-04 11:16 UTCVendor advisory
  36. 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  37. 2026-10-03 13:24 UTCEG score recompute
  38. 2026-10-03 13:24 UTCVendor advisory
  39. 2026-10-02 17:57 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  40. 2026-10-02 15:32 UTCEG score recompute
  41. 2026-10-02 15:32 UTCVendor advisory
  42. 2026-10-01 19:51 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  43. 2026-10-01 17:41 UTCVendor advisory
  44. 2026-09-30 19:45 UTCEG score recompute
  45. 2026-09-30 19:45 UTCVendor advisory
  46. 2026-09-30 15:04 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  47. 2026-09-30 14:36 UTCVendor advisory
  48. 2026-09-29 16:31 UTCEG score recompute
  49. 2026-09-29 15:53 UTCEG score recompute
  50. 2026-09-29 15:38 UTCEG score recomputeFirst assessed: 6.9 MEDIUM
  51. 2026-09-29 15:38 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-97688?
CVE-2026-97688 is a medium-severity vulnerability; its CVE record was published on September 29, 2026. urllib3 is an HTTP client library for Python. From 2.6.2 until 2.8.0, HTTPResponse.stream and HTTPResponse.read_chunked can enter an infinite loop because the Deflate decoder retains trailing bytes as unconsumed input after reaching end-of-stream and repeatedly decodes them without progress. The…
When was the CVE record for CVE-2026-97688 published?
The CVE record for CVE-2026-97688 was published on September 29, 2026. 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 13, 2026; the record at its source may have been updated since.
Is CVE-2026-97688 actively exploited?
CVE-2026-97688 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.3% probability of exploitation in the next 30 days (21st percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-97688?
CVE-2026-97688 has a CVSS v3 base score of 5.3 (NVD).
How do I remediate CVE-2026-97688?
A fix for CVE-2026-97688 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-97688 are linked in the Vendor Advisories panel on this page.

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