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CVE-2026-77528Suited to automated attack · CISA

Autobahn Python permessage-deflate bypasses maxMessagePayloadSize after inflation

CVSS score

5.3

EPSS probability

%0.5

Risk score

0.0

Published

1 mo ago

OverviewPublic Exploits (0)NewsroomVulnerability Timeline
Patch status has not yet been verified

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Vulnerability description

DayBreach CVE AI Research

CVE-2026-77528 has vendor, distribution, patch and security-source records on file. We can compare them and prepare an explanation linked to the evidence.

Autobahn Python is a WebSocket and WAMP implementation for Python that supports Twisted and asyncio. Prior to 26.7.1, WebSocket endpoints that accept permessage-deflate and rely on maxMessagePayloadSize enforce that limit against the compressed frame length before inflation but do not recheck the decompressed message size before delivery. A remote unauthenticated client can send a valid compressed frame below the configured wire-size limit that expands beyond the application message limit, causing oversized data to be allocated, joined, validated, and passed to application callbacks. This can create resource-exhaustion pressure, but the advisory does not establish confidentiality or integrity impact. This issue is fixed in version 26.7.1.

IMPACT: Affected Products and Software

Affected Products

The following products are affected by CVE-2026-77528 vulnerability. Where our threat engine knows the exact affected versions, they are listed below.

IDVENDORPRODUCTACTION
1crossbarioautobahn-python View
2pypiautobahn View
3pypicrossbar View
Total affected vendors: 2|Products: 3

RED HAT CSAF/VEX: Product Impact Check

Red Hat has not yet published a CSAF/VEX impact record for this CVE. This does not mean “not affected”.

SCORING: CVSS from Multiple Sources

CVSS Scores

The Common Vulnerability Scoring System is a standardised framework for assessing the severity of vulnerabilities in software and systems. We collect and display CVSS scores from several sources for each CVE.

SCOREVERSIONSEVERITYVECTORSOURCE
5.3CVSS 3.x—Vector not publishedGitHub Advisory
5.3CVSS V31MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:LNVD
5.3CVSS V3_1MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:LCVE CNA
0.0CVSS 4.0—Vector not publishedGitHub Advisory

Patch and Remediation Guide

Solution & Remediation Advisory

Patch status unknown

İncelenen resmî kaynaklarda yama durumu doğrulanamadı. Bu sonuç “yama yok” anlamına gelmez.

Confirm the affected product and version against the source evidence above.
Restrict access to internet-facing services and apply network segmentation.
Until a patch is confirmed, follow the vendor advisory; do not read an unknown status as “no patch”.
Monitor server logs and network endpoints for signs of anomalous execution.

Public exploit and active exploitation status

Verified exploit intelligence

No verified public PoC, exploit repository or Metasploit module has been found for this CVE yet.

Weakness Classification and Attack Patterns (CWE & CAPEC)

CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorises the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-77528 is associated with the following CWEs:

CWE-409: Common Weakness Enumeration Entry CWE-409CWE-770: Allocation of Resources Without Limits or Throttling

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-77528 weaknesses.

CAPEC-66: SQL InjectionCAPEC-126: Path TraversalCAPEC-28: OS Command Injection

Attack Vector and Accessibility

ExposureAğ üzerinden
PermissionsGerekmiyor
UserGerekmiyor

Official Sources and Advisories

https://github.com/crossbario/autobahn-python/security/advisories/GHSA-hxp9-w8x3-p566vendor-advisoryhttps://github.com/crossbario/autobahn-python/pull/1916vendor-advisoryhttps://github.com/crossbario/autobahn-python/commit/77d323a30b09b1828ad8be2ce6344e056970e613vendor-advisoryhttps://github.com/crossbario/autobahn-python/releases/tag/v26_7_1vendor-advisoryhttps://nvd.nist.gov/vuln/detail/CVE-2026-77528vendor-advisoryhttps://github.com/advisories/GHSA-hxp9-w8x3-p566vendor-advisory

CVSS Vector Radar Chart

5.3 / 10
Attack VectorNetworkComplexityLowPrivilegesNoneUser Interact.NoneConfidentialityLowIntegrityNoneAvailabilityLow

Vulnerability Scoring Details

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredNone required
User InteractionNone required
Confidentiality (Gizlilik)Low
Integrity (Bütünlük)None
Availability (Erişilebilirlik)Low

Yama durumu bilinmiyor

İncelenen resmî kaynaklarda yama durumu doğrulanamadı. Bu sonuç “yama yok” anlamına gelmez.

Follow the vendor

C
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crossbario
P
pypi logo
pypi

Weakness Type (CWE & CAPEC)

CWE-409 CWE-770

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