CVE-2025-64508 | Bugsink vulnerable to unauthenticated remote DoS via crafted Brotli input

Bugsink is a self-hosted error tracking tool. In versions prior to 2.0.5, brotli "bombs" (highly compressed brotli streams, such as many zeros) can be sent to the server. Since the server will attempt to decompress these streams before applying various maximums, this can lead to exhaustion of the available memory and thus a Denial of Service. This can be done if the `DSN` is known, which it is in many common setups (JavaScript, Mobile Apps). The issue is patched in Bugsink version `2.0.5`. The vulnerability is similar to, but distinct from, another brotli-related problem in Bugsink, GHSA-rrx3-2x4g-mq2h/CVE-2025-64509.

Published: 2025-11-10 Last update: 2026-04-15 Assigner: [email protected] Source: [email protected]

Conclusion & alert: CVE-2025-64508 is rated Moderate Risk (45.2/100): CVSS High severity, with low exploitation likelihood (EPSS 0.21%). Mandatory action: Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2025-64508

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-04-20 0.15% 0.21% +0.06%
2 2026-04-09 0.22% 0.15% -0.07%
3 2026-03-12 0.22%

Full EPSS history (4 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2025-64508

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
3.9 3.6 [email protected]

Weakness enumeration for CVE-2025-64508

GitHub Security Advisory for CVE-2025-64508

GHSA-fc2v-vcwj-269v · Severity: high · Ecosystem: pip — Bugsink is vulnerable to unauthenticated remote DoS via crafted Brotli input

Affected software / configurations for CVE-2025-64508

Vendor Product Version Raw CPE
No affected products in dataset.

References for CVE-2025-64508

cvelogic Threat Intelligence