> CVE-2026-49855 [HIGH]

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PUBLISHED
2026-07-14 21:17
MODIFIED
2026-07-14 21:17
CVSS_SCORE V3
7.5
EPSS (Prob. Exploit)
0.57%
Top 52.7%
DATA SOURCES:
NVD 🔗 2026-07-14 CWE MITRE 🔗 2026-11-01 FIRST EPSS 🔗 2026-11-01 GITHUB 🔗 2026-11-05 OSV 🔗 2026-10-26

> DESCRIPTION

Tornado is a Python web framework and asynchronous networking library. Prior to 6.5.6, Tornado gzip decompression routines processed limited-size chunks but did not enforce an overall limit on accumulated decompressed chunks, allowing a malicious server accessed by SimpleAsyncHTTPClient or an HTTPServer configured with decompress_request=True to consume effectively unlimited memory. This issue is fixed in version 6.5.6.

> AFFECTED_PRODUCTS

ℹ️ Aucun produit affecté n'a encore été publié par NVD pour cette CVE.

> CVSS V3 METRICS

CVSS_VECTOR
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EXPLOITABILITY
3.9
IMPACT
3.6

> MÉTRIQUES CVSS DÉTAILLÉES

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Métrique Valeur Interprétation
AV (Vecteur d'Attaque)
Attack Vector
Network (N)
Exploit possible à distance via réseau (HTTP, API, etc.)
AC (Complexité d'Attaque)
Attack Complexity
Low (L)
Peu de conditions requises pour exploiter
PR (Privilèges Requis)
Privileges Required
None (N)
Aucune authentification requise
UI (Interaction Utilisateur)
User Interaction
None (N)
Aucune interaction utilisateur nécessaire
S (Périmètre)
Scope
Unchanged (U)
Impact reste dans le périmètre du composant compromis
C (Impact Confidentialité)
Confidentiality Impact
None (N)
Aucune divulgation d'informations
I (Impact Intégrité)
Integrity Impact
None (N)
Aucune modification de données possible
A (Impact Disponibilité)
Availability Impact
High (H)
Interruption totale du service possible

> RÉSUMÉ DES IMPACTS

Confidentialité
None
Aucune divulgation d'informations
Intégrité
None
Aucune modification de données possible
Disponibilité
High
Interruption totale du service possible

> WEAKNESSES

CWE-409

> CWE DETAILED DESCRIPTIONS

CWE-409: Improper Handling of Highly Compressed Data (Data Amplification) - The product does not handle or incorrectly handles a compressed input with a very high compression ratio that produces a large output.

> RED HAT SECURITY ADVISORIES

Red Hat Security Advisory: python-tornado security update
An update for python-tornado is now available for Red Hat Enterprise Linux 9. Red Hat Product Security has rated this update as having a security impact of Important. A Common Vulnerability Scoring S...
Red Hat Security Advisory: python-tornado security update
An update for python-tornado is now available for Red Hat Enterprise Linux 10. Red Hat Product Security has rated this update as having a security impact of Important. A Common Vulnerability Scoring...
Red Hat Security Advisory: RHOAI 3.3.7 - Red Hat OpenShift AI
Updated images are now available for Red Hat OpenShift AI.
Red Hat Security Advisory: python-tornado security update
An update for python-tornado is now available for Red Hat Enterprise Linux 10.0 Extended Update Support. Red Hat Product Security has rated this update as having a security impact of Important. A Com...
Red Hat Security Advisory: RHOAI 3.4.5 - Red Hat OpenShift AI
Updated images are now available for Red Hat OpenShift AI.
Red Hat Security Advisory: RHOAI 2.25.12 - Red Hat OpenShift AI
Updated images are now available for Red Hat OpenShift AI.
Red Hat Security Advisory: RHOAI 3.5.2 - Red Hat OpenShift AI
Updated images are now available for Red Hat OpenShift AI.
Red Hat Security Advisory: python-tornado security update
An update for python-tornado is now available for Red Hat Enterprise Linux 9.6 Extended Update Support. Red Hat Product Security has rated this update as having a security impact of Important. A Comm...

> GITHUB SECURITY ADVISORY

GHSA-mgf9-4vpg-hj56 HIGH

tornado AsyncHTTPClient accumulates decompressed chunks without size limit (gzip bomb)

AFFECTED PACKAGES:
PIP / tornado
< 6.5.6
Fixed in: 6.5.6

> OSV (GOOGLE OPEN SOURCE VULNERABILITIES)

tornado AsyncHTTPClient accumulates decompressed chunks without size limit (gzip bomb)

AFFECTED PACKAGES:
Unknown / Unknown
54 versions affected
ALIASES:
GHSA-mgf9-4vpg-hj56, PYSEC-2026-3389

> HISTORIQUE DES MODIFICATIONS

Première apparition
14/07/2026 21:17
Source: NVD
📊 ENRICHISSEMENT 01/11/2026 06:59
CWE
Champ modifié: Description CWE
Ancienne valeur:
CWE-409: Improper Handling of Highly Compressed Data (Data Amplification) - The product does not handle or incorrectly handles a compressed input with a very high compression ratio that produces a lar...
Nouvelle valeur:
CWE-409: Improper Handling of Highly Compressed Data (Data Amplification) - The product does not handle or incorrectly handles a compressed input with a very high compression ratio t...
📊 ENRICHISSEMENT 01/08/2026 06:01
CWE
Champ modifié: Description CWE
Ancienne valeur:
N/A
Nouvelle valeur:
CWE-409: Improper Handling of Highly Compressed Data (Data Amplification) - The product does not handle or incorrectly handles a compressed input with a very high compression ratio that produces a lar...
Total des modifications: 2 Dernière mise à jour: 5 days ago

> REFERENCES

https://github.com/tornadoweb/tornado/commit/ff808b33adc52d89a549376a5e3628e92ab...
https://github.com/tornadoweb/tornado/pull/3626
https://github.com/tornadoweb/tornado/security/advisories/GHSA-mgf9-4vpg-hj56
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