CVE-2026-15267.5HighCWE-409

CVE-2026-1526: undici is vulnerable to Unbounded Memory Consumption in undici WebSocket permessage-deflate Decompression

undici

Vendor fix available · Affected: undici · Exploitation: possible (1 to 10%)

Not in CyberSIXT coverage yet: no article names this CVE. This page shows the public record.

1.3%probability of exploitation in the next 30 days

70th percentile

050100

Higher than 70% of scored CVEs

7.5HighCVSS 3.1

LowMediumHighCrit.

DescriptionCVE.org

The undici WebSocket client is vulnerable to a denial-of-service attack via unbounded memory consumption during permessage-deflate decompression. When a WebSocket connection negotiates the permessage-deflate extension, the client decompresses incoming compressed frames without enforcing any limit on the decompressed data size. A malicious WebSocket server can send a small compressed frame (a "decompression bomb") that expands to an extremely large size in memory, causing the Node.js process to exhaust available memory and crash or become unresponsive. The vulnerability exists in the PerMessageDeflate.decompress() method, which accumulates all decompressed chunks in memory and concatenates them into a single Buffer without checking whether the total size exceeds a safe threshold.

Affected products1

From the CVE record. A product or version that is not listed is unknown, not unaffected.

undici · undici< 6.24.0; 7.0.0 < 7.24.0

On the Atlas

Every published CVE is on the CyberSIXT Atlas, grouped by weakness, vendor and month.

Open the Atlas

Exploitation: Possible (1 to 10%). EPSS between 1% and 10%.
CISA KEV: Not listed
Public check: No public nuclei template
Weakness: Improper Handling of Highly Compressed Data (Data Amplification) · Denial of Service
Vendor: undici
Published: March 2026
Band: Possible (1 to 10%), March 2026

CoverageNo articles yet

No CyberSIXT article names CVE-2026-1526 yet, so there is no coverage timeline, action brief or change log for it. Everything on this page comes from the public CVE record, CISA KEV, EPSS and the nuclei template index. Search the archive or see the CVEs in the news.

References

11 more references are in the CVE record.