CVE-2026-48802

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 76% 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. Prior to version 4.13.2, an attacker can cause the creation of unnecessary background threads in the python-engineio server by exploiting the heartbeat mechanism, which launches a thread when a new connection is received, and when the client sends a PONG packet. This issue primarily affects synchronous servers. Asynchronous servers allocate background tasks instead of physical threads, which are lightweight and less likely to cause denial of service. However, the fix that was implemented was also applied to the asynchronous case. Version 4.13.2 addresses this issue as follows: The initial background thread (or async task( for heartbeat management is only launched if a client passes authentication in the connect handler; and the server now ensures that there is only one background heatbeat thread (or async task) per client at a given point in time. Out of sequence PONG packets are now discarded when an active heartbeat thread is already running.

CVSS v3
7.5
EG Score
7.5(medium)
EG Risk
49(Track)
EG Risk 49/100SSVC: 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%
Automatability100% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
24%
KEV
Not listed

Published

June 26, 2026

Last Modified

August 13, 2026

Advisory Details (2)

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

advisory-database/vulns/python-engineio/PYSEC-2026-3032.yaml at main · pypa/advisory-database · GitHub

https://github.com/pypa/advisory-database/tree/main/vulns/python-engineio/PYSEC-2026-3032.yaml
github Patch Available

Unbound thread allocation can cause denial of service · Advisory · miguelgrinberg/python-engineio · GitHub

https://github.com/miguelgrinberg/python-engineio/security/advisories/GHSA-cgwc-pv48-fhj5

Vendor Advisories for CVE-2026-48802(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 / 42× 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 23:00 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. 2026-08-25 01:36 UTCEG score recompute
  20. 2026-08-24 12:52 UTCEG score recompute
  21. 2026-08-23 11:09 UTCEG score recompute
  22. 2026-08-23 00:19 UTCEPSS rescore
  23. 2026-08-22 09:42 UTCEG score recompute
  24. 2026-08-21 23:49 UTCEPSS rescore
  25. 2026-08-21 08:12 UTCEG score recompute
Show 23 more
  1. 2026-08-20 22:55 UTCEPSS rescore
  2. 2026-08-20 06:44 UTCEG score recompute
  3. 2026-08-19 17:04 UTCEPSS rescore
  4. 2026-08-18 23:42 UTCEG score recompute
  5. 2026-08-18 13:48 UTCEPSS rescore
  6. 2026-08-17 13:47 UTCEPSS rescore
  7. 2026-08-16 20:00 UTCEG score recompute
  8. 2026-08-16 14:56 UTCEPSS rescore
  9. 2026-08-16 07:08 UTCEG score recompute
  10. 2026-08-16 02:14 UTCEPSS rescore
  11. 2026-08-15 05:41 UTCEG score recompute
  12. 2026-08-15 01:30 UTCEPSS rescore
  13. 2026-08-14 04:12 UTCEG score recompute
  14. 2026-08-13 22:00 UTCEPSS rescore
  15. 2026-08-13 15:28 UTCEG score recompute
  16. 2026-08-13 15:17 UTCEG score recompute
  17. 2026-08-12 20:47 UTCEG score recompute
  18. 2026-08-12 13:51 UTCEPSS rescore
  19. 2026-08-11 19:19 UTCEG score recompute
  20. 2026-07-30 13:21 UTCEG score recompute
  21. 2026-07-26 14:31 UTCEG score recompute
  22. 2026-07-23 03:18 UTCEG score recompute
  23. 2026-06-26 21:40 UTCEG score recompute

Frequently asked(5)

What is CVE-2026-48802?
CVE-2026-48802 is a high vulnerability published on June 26, 2026. python-engineio is a Python implementation of the Engine.IO realtime client and server. Prior to version 4.13.2, an attacker can cause the creation of unnecessary background threads in the python-engineio server by exploiting the heartbeat mechanism, which launches a thread when a new connection is…
When was CVE-2026-48802 disclosed?
CVE-2026-48802 was first published in the National Vulnerability Database on June 26, 2026, with the most recent update on August 13, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-48802 actively exploited?
CVE-2026-48802 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 75.5% of all scored CVEs.
What is the CVSS score of CVE-2026-48802?
CVE-2026-48802 has a CVSS v3 base score of 7.5 (NVD).
How do I remediate CVE-2026-48802?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-48802, 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

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-48802

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