ALAS2-2026-3852

Amazon Linux 2 Security Advisory: ALAS2-2026-3852
Advisory Released Date: 2026-08-04
Advisory Updated Date: 2026-08-04
Severity: Important
Issue Overview:

CR/LF bytes were not rejected by HTTP client proxy tunnel headers or host. (CVE-2026-1502)

The incremental HTML parser (html.parser.HTMLParser) allows for CPU
denial-of-service through repeated unterminated markup declarations when
processing uncontrolled data. (CVE-2026-15308)

When calling base64.b64decode() or related functions the decoding process would stop after encountering the first padded quad regardless of whether there was more information to be processed. This can lead to data being accepted which may be processed differently by other implementations. Use "validate=True" to enable stricter processing of base64 data. (CVE-2026-3446)


Affected Packages:

python3


Note:

This advisory is applicable to Amazon Linux 2 (AL2) Core repository. Visit this FAQ section for the difference between AL2 Core and AL2 Extras advisories.


Issue Correction:
Run yum update python3 or yum update --advisory ALAS2-2026-3852 to update your system.

New Packages:
aarch64:
    python3-3.7.16-1.amzn2.0.29.aarch64
    python3-libs-3.7.16-1.amzn2.0.29.aarch64
    python3-devel-3.7.16-1.amzn2.0.29.aarch64
    python3-tools-3.7.16-1.amzn2.0.29.aarch64
    python3-tkinter-3.7.16-1.amzn2.0.29.aarch64
    python3-test-3.7.16-1.amzn2.0.29.aarch64
    python3-debug-3.7.16-1.amzn2.0.29.aarch64
    python3-debuginfo-3.7.16-1.amzn2.0.29.aarch64

i686:
    python3-3.7.16-1.amzn2.0.29.i686
    python3-libs-3.7.16-1.amzn2.0.29.i686
    python3-devel-3.7.16-1.amzn2.0.29.i686
    python3-tools-3.7.16-1.amzn2.0.29.i686
    python3-tkinter-3.7.16-1.amzn2.0.29.i686
    python3-test-3.7.16-1.amzn2.0.29.i686
    python3-debug-3.7.16-1.amzn2.0.29.i686
    python3-debuginfo-3.7.16-1.amzn2.0.29.i686

src:
    python3-3.7.16-1.amzn2.0.29.src

x86_64:
    python3-3.7.16-1.amzn2.0.29.x86_64
    python3-libs-3.7.16-1.amzn2.0.29.x86_64
    python3-devel-3.7.16-1.amzn2.0.29.x86_64
    python3-tools-3.7.16-1.amzn2.0.29.x86_64
    python3-tkinter-3.7.16-1.amzn2.0.29.x86_64
    python3-test-3.7.16-1.amzn2.0.29.x86_64
    python3-debug-3.7.16-1.amzn2.0.29.x86_64
    python3-debuginfo-3.7.16-1.amzn2.0.29.x86_64

Additional References

Release Notes:  Amazon Linux 2 Release Notes

Red Hat: CVE-2026-1502, CVE-2026-15308, CVE-2026-3446

Mitre: CVE-2026-1502, CVE-2026-15308, CVE-2026-3446