CVE-2026-48809

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: 0.5% (41st 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

Also known asEUVD-2026-56854 (ENISA EUVD) · GHSA-m9gh-vj53-gvh9 (GitHub Security Advisories)Source: ENISA EUVD

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: 0.5%CVSS: 7.5Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

python-engineio is a Python implementation of the Engine.IO realtime client and server. Versions prior to 4.13.2 have two specific configurations of the python-engineio server in which the size of incoming messages is not checked before the messages are loaded into memory. An attacker can take advantage of these to cause unnecessary memory allocations in the python-engineio server. The two cases are POST requests, when using ASGI with the long polling transport and WebSocket messages, when using Aiohttp with the WebSocket transport. Version 4.13.2 addresses this issue. ASGI severs now only load the body of incoming requests into memory after the client is confirmed to be known and authenticated, and the payload size is below the maximum allowed size. Requests that do not comply with these requirements are discarded. Aiohttp servers configure the maximum payload size in the underlying WebSocket layer from Aiohttp, so that large messages are discarded by Aiohttp before they are delivered to python-engineio.

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 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)
Severity75% × 45%
Impact severity (EG Severity): CVSS 7.5 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0.5% × 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
0.5%
EPSS %ILE
41st
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 (7.5): severity, escalated by confirmed exploitation. This CVE's 7.5 is its impact severity (EG Severity), not escalated.

EG Severity
7.5 HIGHCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.a secondary CVSS source · CVSS v3.0 or v3.1
EG Likelihood
0.5% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-24). 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: 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.

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

June 26, 2026

Last Modified

September 18, 2026

Advisory Details (2)

Auto-updated Aug 11, 2026
Patch available. Sources: github.
Web page

advisory-database/vulns/python-engineio/PYSEC-2026-3033.yaml at main · pypa/advisory-database · GitHub

https://github.com/pypa/advisory-database/tree/main/vulns/python-engineio/PYSEC-2026-3033.yaml
GitHub advisoryMentions a patch (unverified)

Possible denial of service due to maximum payload size sometimes not being enforced · Advisory · miguelgrinberg/python-engineio · GitHub

https://github.com/miguelgrinberg/python-engineio/security/advisories/GHSA-m9gh-vj53-gvh9

Vendor Advisories for CVE-2026-48809(1)

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

Affected Packages

(4 across 4 ecosystems)
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
python-engineio4.11.1-0.1 ... 4.9.0-2 (11 versions)
  • every version on: no fix on record
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
python-engineio4.11.2-1 ... 4.14.0-1 (6 versions)
  • every version on: no fix on record
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
python-engineio4.11.2-1, 4.12.1-1, 4.12.1-2, 4.13.0-1, 4.13.0-2
  • every version up to 4.14.0-1: fixed in 4.14.0-1
—
PyPI(1)
PackageVulnerable rangeFix by version rangeDependents
python-engineio0.1.0 ... 4.9.1 (143 versions)
  • every version up to 4.13.2: fixed in 4.13.2
—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 9× in last 7d / 37× 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. 2026-10-27 16:32 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  2. 2026-10-26 16:31 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  3. 2026-10-25 16:33 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  4. 2026-10-25 14:23 UTCEG score recompute
  5. 2026-10-24 16:33 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  6. 2026-10-23 20:01 UTCEG score recompute
  7. 2026-10-23 16:32 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  8. 2026-10-22 16:34 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  9. 2026-10-21 16:33 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  10. 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  11. 2026-10-19 16:32 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  12. 2026-10-18 16:32 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  13. 2026-10-18 03:34 UTCEG score recompute
  14. 2026-10-17 16:34 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  15. 2026-10-17 12:14 UTCEG score recompute
  16. 2026-10-16 16:42 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  17. 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  18. 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  19. 2026-10-13 20:54 UTCOSV refresh
  20. 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  21. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  22. 2026-10-12 16:00 UTCEG score recompute
  23. 2026-10-11 19:43 UTCEG score recompute
  24. 2026-10-11 16:58 UTCEG score recompute
  25. 2026-10-11 14:22 UTCEG score recompute
Show 71 more
  1. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  2. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  3. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  4. 2026-10-08 17:12 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  5. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  6. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  7. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  8. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  9. 2026-10-03 14:25 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  10. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  11. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  12. 2026-09-28 13:51 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  13. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  14. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  15. 2026-09-26 00:27 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  16. 2026-09-23 17:53 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  17. 2026-09-23 07:48 UTCEG score recompute
  18. 2026-09-20 20:16 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  19. 2026-09-18 20:36 UTCEG score recompute
  20. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  21. 2026-09-18 07:11 UTCEG score recompute
  22. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  23. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  24. 2026-09-14 01:00 UTCEG score recompute
  25. 2026-09-13 16:47 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  26. 2026-09-12 15:33 UTCEG score recompute
  27. 2026-09-11 14:53 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  28. 2026-09-10 09:35 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  29. 2026-09-08 22:01 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  30. 2026-09-07 16:01 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  31. 2026-09-06 15:01 UTCEG score recompute
  32. 2026-09-06 13:47 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  33. 2026-09-04 05:06 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  34. 2026-09-02 14:12 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  35. 2026-09-01 13:54 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  36. 2026-09-01 04:40 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  37. 2026-08-30 19:20 UTCEG score recompute
  38. 2026-08-30 19:17 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  39. 2026-08-30 01:22 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  40. 2026-08-28 21:41 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  41. 2026-08-27 23:01 UTCEG score recompute
  42. 2026-08-27 14:25 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  43. 2026-08-26 14:46 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  44. 2026-08-25 13:49 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  45. 2026-08-24 21:47 UTCEG score recompute
  46. 2026-08-23 08:31 UTCEG score recompute
  47. 2026-08-23 00:19 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  48. 2026-08-22 09:24 UTCEG score recompute
  49. 2026-08-21 23:49 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  50. 2026-08-21 05:08 UTCEG score recompute
  51. 2026-08-20 22:55 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  52. 2026-08-20 06:44 UTCEG score recompute
  53. 2026-08-19 17:04 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  54. 2026-08-18 23:42 UTCEG score recompute
  55. 2026-08-18 13:48 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  56. 2026-08-17 13:47 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  57. 2026-08-17 00:26 UTCEG score recompute
  58. 2026-08-16 14:56 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  59. 2026-08-16 13:17 UTCEG score recompute
  60. 2026-08-16 02:14 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  61. 2026-08-15 03:50 UTCEG score recompute
  62. 2026-08-15 01:30 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  63. 2026-08-14 05:31 UTCEG score recompute
  64. 2026-08-13 22:00 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  65. 2026-08-12 18:39 UTCEG score recompute
  66. 2026-08-12 13:51 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  67. 2026-08-11 19:19 UTCEG score recompute
  68. 2026-07-30 11:33 UTCEG score recompute
  69. 2026-07-26 14:31 UTCEG score recompute
  70. 2026-07-23 03:18 UTCEG score recompute
  71. 2026-06-26 21:40 UTCEG score recompute

Frequently asked(5)

What is CVE-2026-48809?
CVE-2026-48809 is a high-severity vulnerability; its CVE record was published on June 26, 2026. python-engineio is a Python implementation of the Engine.IO realtime client and server. Versions prior to 4.13.2 have two specific configurations of the python-engineio server in which the size of incoming messages is not checked before the messages are loaded into memory. An attacker can take…
When was the CVE record for CVE-2026-48809 published?
The CVE record for CVE-2026-48809 was published on June 26, 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 September 18, 2026; the record at its source may have been updated since.
Is CVE-2026-48809 actively exploited?
CVE-2026-48809 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.5% probability of exploitation in the next 30 days (41st percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-48809?
CVE-2026-48809 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-2026-48809?
A fix for CVE-2026-48809 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-48809 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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