Amazon Linux 2023 Security Advisory: ALAS2023-2026-1618
Advisory Released Date: 2026-04-30
Advisory Updated Date: 2026-04-30
The fix for CVE-2026-0672, which rejected control characters in http.cookies.Morsel, was incomplete. The Morsel.update(), |= operator, and unpickling paths were not patched, allowing control characters to bypass input validation. Additionally, BaseCookie.js_output() lacked the output validation applied to BaseCookie.output(). (CVE-2026-3644)
Mitgation of CVE-2026-4519 was incomplete. If the URL contained "%action" the mitigation could be bypassed for certain browser types the "webbrowser.open()" API could have commands injected into the underlying shell. See CVE-2026-4519 for details. (CVE-2026-4786)
Use-after-free (UAF) was possible in the `lzma.LZMADecompressor`, `bz2.BZ2Decompressor`, and `gzip.GzipFile` when a memory allocation fails with a `MemoryError` and the decompression instance is re-used. This scenario can be triggered if the process is under memory pressure. The fix cleans up the dangling pointer in this specific error condition.
The vulnerability is only present if the program re-uses decompressor instances across multiple decompression calls even after a `MemoryError` is raised during decompression. Using the helper functions to one-shot decompress data such as `lzma.decompress()`, `bz2.decompress()`, `gzip.decompress()`, and `zlib.decompress()` are not affected as a new decompressor instance is used per call. If the decompressor instance is not re-used after an error condition, this usage is similarly not vulnerable. (CVE-2026-6100)
Affected Packages:
python3.9
Issue Correction:
Run dnf update python3.9 --releasever 2023.11.20260427 or dnf update --advisory ALAS2023-2026-1618 --releasever 2023.11.20260427 to update your system.
More information on how to update your system can be found on this page: Amazon Linux 2023 documentation
aarch64:
python3-3.9.25-1.amzn2023.0.5.aarch64
python3-tkinter-3.9.25-1.amzn2023.0.5.aarch64
python3-devel-3.9.25-1.amzn2023.0.5.aarch64
python3.9-debugsource-3.9.25-1.amzn2023.0.5.aarch64
python3-idle-3.9.25-1.amzn2023.0.5.aarch64
python3-debug-3.9.25-1.amzn2023.0.5.aarch64
python3.9-debuginfo-3.9.25-1.amzn2023.0.5.aarch64
python3-libs-3.9.25-1.amzn2023.0.5.aarch64
python3-test-3.9.25-1.amzn2023.0.5.aarch64
noarch:
python-unversioned-command-3.9.25-1.amzn2023.0.5.noarch
src:
python3.9-3.9.25-1.amzn2023.0.5.src
x86_64:
python3-devel-3.9.25-1.amzn2023.0.5.x86_64
python3-test-3.9.25-1.amzn2023.0.5.x86_64
python3.9-debugsource-3.9.25-1.amzn2023.0.5.x86_64
python3-3.9.25-1.amzn2023.0.5.x86_64
python3-idle-3.9.25-1.amzn2023.0.5.x86_64
python3-tkinter-3.9.25-1.amzn2023.0.5.x86_64
python3-debug-3.9.25-1.amzn2023.0.5.x86_64
python3-libs-3.9.25-1.amzn2023.0.5.x86_64
python3.9-debuginfo-3.9.25-1.amzn2023.0.5.x86_64