CVE-2026-48809

HIGHPre-NVD 7.57.5—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 7.5 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.3%, top 80% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
7.5EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 7.5Exploit: None knownExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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
7.5(medium)
EG Risk
38(Track)
EG Risk 38/100SSVC: Track

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
Severity75% × 45%
Exploitation0% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
20%
KEV
Not listed

Published

June 26, 2026

Last Modified

August 11, 2026

Advisory Details (2)

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

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 Patch Available

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 rangeFixed inDependents
python-engineio4.11.1-0.1 ... 4.9.0-2 (10 versions)——
Debian:13(1)
PackageVulnerable rangeFixed inDependents
python-engineio4.11.2-1, 4.12.1-1, 4.12.1-2, 4.13.0-1, 4.13.0-2——
Debian:14(1)
PackageVulnerable rangeFixed inDependents
python-engineio4.11.2-1, 4.12.1-1, 4.12.1-2, 4.13.0-1, 4.13.0-2——
PyPI(1)
PackageVulnerable rangeFixed inDependents
python-engineio0.1.0 ... 4.9.1 (143 versions)4.13.2—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 6× in last 7d / 38× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. 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. Most recent first.

  1. 2026-09-11 14:53 UTCEPSS rescore
  2. 2026-09-10 09:35 UTCEPSS rescore
  3. 2026-09-08 22:01 UTCEPSS rescore
  4. 2026-09-07 16:01 UTCEPSS rescore
  5. 2026-09-06 15:01 UTCEG score recompute
  6. 2026-09-06 13:47 UTCEPSS rescore
  7. 2026-09-04 05:06 UTCEPSS rescore
  8. 2026-09-02 14:12 UTCEPSS rescore
  9. 2026-09-01 13:54 UTCEPSS rescore
  10. 2026-09-01 04:40 UTCEPSS rescore
  11. 2026-08-30 19:20 UTCEG score recompute
  12. 2026-08-30 19:17 UTCEPSS rescore
  13. 2026-08-30 01:22 UTCEPSS rescore
  14. 2026-08-28 21:41 UTCEPSS rescore
  15. 2026-08-27 23:01 UTCEG score recompute
  16. 2026-08-27 14:25 UTCEPSS rescore
  17. 2026-08-26 14:46 UTCEPSS rescore
  18. 2026-08-25 13:49 UTCEPSS rescore
  19. 2026-08-24 21:47 UTCEG score recompute
  20. 2026-08-23 08:31 UTCEG score recompute
  21. 2026-08-23 00:19 UTCEPSS rescore
  22. 2026-08-22 09:24 UTCEG score recompute
  23. 2026-08-21 23:49 UTCEPSS rescore
  24. 2026-08-21 05:08 UTCEG score recompute
  25. 2026-08-20 22:55 UTCEPSS rescore
Show 20 more
  1. 2026-08-20 06:44 UTCEG score recompute
  2. 2026-08-19 17:04 UTCEPSS rescore
  3. 2026-08-18 23:42 UTCEG score recompute
  4. 2026-08-18 13:48 UTCEPSS rescore
  5. 2026-08-17 13:47 UTCEPSS rescore
  6. 2026-08-17 00:26 UTCEG score recompute
  7. 2026-08-16 14:56 UTCEPSS rescore
  8. 2026-08-16 13:17 UTCEG score recompute
  9. 2026-08-16 02:14 UTCEPSS rescore
  10. 2026-08-15 03:50 UTCEG score recompute
  11. 2026-08-15 01:30 UTCEPSS rescore
  12. 2026-08-14 05:31 UTCEG score recompute
  13. 2026-08-13 22:00 UTCEPSS rescore
  14. 2026-08-12 18:39 UTCEG score recompute
  15. 2026-08-12 13:51 UTCEPSS rescore
  16. 2026-08-11 19:19 UTCEG score recompute
  17. 2026-07-30 11:33 UTCEG score recompute
  18. 2026-07-26 14:31 UTCEG score recompute
  19. 2026-07-23 03:18 UTCEG score recompute
  20. 2026-06-26 21:40 UTCEG score recompute

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-48809?
CVE-2026-48809 is a high vulnerability 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 CVE-2026-48809 disclosed?
CVE-2026-48809 was first published in the National Vulnerability Database on June 26, 2026, with the most recent update on August 11, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-48809 actively exploited?
CVE-2026-48809 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 79.8% of all scored CVEs.
What is the CVSS score of CVE-2026-48809?
CVE-2026-48809 has a CVSS v3 base score of 7.5 (NVD).
How do I remediate CVE-2026-48809?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-48809, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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