9.8

CVE-2026-27820

zlib: Buffer Overflow in Zlib::GzipReader ungetc via large input leads to memory corruption

zlib is a Ruby interface for the zlib compression/decompression library. Versions 3.0.0 and below, 3.1.0, 3.1.1, 3.2.0 and 3.2.1 contain a buffer overflow vulnerability in the Zlib::GzipReader. The zstream_buffer_ungets function prepends caller-provided bytes ahead of previously produced output but fails to guarantee the backing Ruby string has enough capacity before the memmove shifts the existing data. This can lead to memory corruption when the buffer length exceeds capacity. This issue has been fixed in versions 3.0.1, 3.1.2 and 3.2.3.
Daten sind bereitgestellt durch National Vulnerability Database (NVD)
Ruby-lang ≫ Zlib SwPlatformruby Version < 3.0.1
Ruby-lang ≫ Zlib SwPlatformruby Version >= 3.1.0 < 3.1.2
Ruby-lang ≫ Zlib SwPlatformruby Version >= 3.2.0 < 3.2.3
Zu dieser CVE wurde keine Warnung gefunden.
EPSS Metriken
Typ Quelle Score Percentile
EPSS FIRST.org 0.56% 0.421
CVSS Metriken
Quelle Base Score Exploit Score Impact Score Vector String
nvd@nist.gov 9.8 3.9 5.9
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
security-advisories@github.com 1.7 0 0
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:U/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CWE-120 Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')

The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer.

CWE-131 Incorrect Calculation of Buffer Size

The product does not correctly calculate the size to be used when allocating a buffer, which could lead to a buffer overflow.

https://github.com/ruby/zlib/security/advisories/GHSA-g857-hhfv-j68w
Vendor Advisory
https://hackerone.com/reports/3467067
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