CVE-2026-41991

GNU gzip contains a vulnerability in the gzexe utility related to insecure temporary file handling. When the mktemp utility is not available in the user’s PATH, gzexe falls back to constructing a temporary file path based solely on the process ID (PID). This predictable filename is created without exclusive access or existence checks. A local attacker can pre‑create the predicted temporary file path as a symbolic link pointing to an arbitrary file writable by the victim. When gzexe runs, it follows the symlink and overwrites the target file, resulting in a time‑of‑check to time‑of‑use (TOCTOU) condition that allows arbitrary file overwrite. This issue has been fixed in the commit 4e6f8b24ab823146ab8776f0b7fe486ab34d4269

GNU gzip contains a vulnerability in the gzexe utility related to insecure temporary file handling. When the mktemp utility is not available in the user’s PATH, gzexe falls back to constructing a temporary file path based solely on the process ID (PID). This predictable filename is created without exclusive access or existence checks. A local attacker can pre‑create the predicted temporary file path as a symbolic link pointing to an arbitrary file writable by the victim. When gzexe runs, it follows the symlink and overwrites the target file, resulting in a time‑of‑check to time‑of‑use (TOCTOU) condition that allows arbitrary file overwrite.

This issue has been fixed in the commit 4e6f8b24ab823146ab8776f0b7fe486ab34d4269

gzip is a single-file/stream lossless data compression utility, where the resulting compressed file generally has the suffix .gz.

Security Fix(es):

GNU gzip contains a vulnerability in the gzexe utility related to insecure temporary file handling. When the mktemp utility is not available in the user’s PATH, gzexe falls back to constructing a temporary file path based solely on the process ID (PID). This predictable filename is created without exclusive access or existence checks. A local attacker can pre‑create the predicted temporary file path as a symbolic link pointing to an arbitrary file writable by the victim. When gzexe runs, it follows the symlink and overwrites the target file, resulting in a time‑of‑check to time‑of‑use (TOCTOU) condition that allows arbitrary file overwrite.

This issue has been fixed in the commit 4e6f8b24ab823146ab8776f0b7fe486ab34d4269(CVE-2026-41991)

GNU gzip contains a global buffer overflow vulnerability in the LZH decompression logic caused by improper reuse of shared global state between different decompression formats within a single execution. GNU gzip maintains a global array that is shared across the LZ77, LZW, and LZH decompression routines and is not reinitialized between files processed in the same invocation. By decompressing a specially crafted LZW file followed by a specially crafted LZH file in a single gzip -d command, an attacker can poison the shared global state and subsequently trigger an out‑of‑bounds read in the LZH decoder. The LZH decompression logic follows stale values left in the shared array, causing reads past the end of the allocated global buffer.

This issue has been fixed in the commit 63dbf6b3b9e6e781df1a6a64e609b10e23969681(CVE-2026-41992)

gzip is a single-file/stream lossless data compression utility, where the resulting compressed file generally has the suffix .gz.

Security Fix(es):

GNU gzip contains a vulnerability in the gzexe utility related to insecure temporary file handling. When the mktemp utility is not available in the user’s PATH, gzexe falls back to constructing a temporary file path based solely on the process ID (PID). This predictable filename is created without exclusive access or existence checks. A local attacker can pre‑create the predicted temporary file path as a symbolic link pointing to an arbitrary file writable by the victim. When gzexe runs, it follows the symlink and overwrites the target file, resulting in a time‑of‑check to time‑of‑use (TOCTOU) condition that allows arbitrary file overwrite.

This issue has been fixed in the commit 4e6f8b24ab823146ab8776f0b7fe486ab34d4269(CVE-2026-41991)

GNU gzip contains a global buffer overflow vulnerability in the LZH decompression logic caused by improper reuse of shared global state between different decompression formats within a single execution. GNU gzip maintains a global array that is shared across the LZ77, LZW, and LZH decompression routines and is not reinitialized between files processed in the same invocation. By decompressing a specially crafted LZW file followed by a specially crafted LZH file in a single gzip -d command, an attacker can poison the shared global state and subsequently trigger an out‑of‑bounds read in the LZH decoder. The LZH decompression logic follows stale values left in the shared array, causing reads past the end of the allocated global buffer.

This issue has been fixed in the commit 63dbf6b3b9e6e781df1a6a64e609b10e23969681(CVE-2026-41992)

gzip is a single-file/stream lossless data compression utility, where the resulting compressed file generally has the suffix .gz.

Security Fix(es):

GNU gzip contains a vulnerability in the gzexe utility related to insecure temporary file handling. When the mktemp utility is not available in the user’s PATH, gzexe falls back to constructing a temporary file path based solely on the process ID (PID). This predictable filename is created without exclusive access or existence checks. A local attacker can pre‑create the predicted temporary file path as a symbolic link pointing to an arbitrary file writable by the victim. When gzexe runs, it follows the symlink and overwrites the target file, resulting in a time‑of‑check to time‑of‑use (TOCTOU) condition that allows arbitrary file overwrite.

This issue has been fixed in the commit 4e6f8b24ab823146ab8776f0b7fe486ab34d4269(CVE-2026-41991)

GNU gzip contains a global buffer overflow vulnerability in the LZH decompression logic caused by improper reuse of shared global state between different decompression formats within a single execution. GNU gzip maintains a global array that is shared across the LZ77, LZW, and LZH decompression routines and is not reinitialized between files processed in the same invocation. By decompressing a specially crafted LZW file followed by a specially crafted LZH file in a single gzip -d command, an attacker can poison the shared global state and subsequently trigger an out‑of‑bounds read in the LZH decoder. The LZH decompression logic follows stale values left in the shared array, causing reads past the end of the allocated global buffer.

This issue has been fixed in the commit 63dbf6b3b9e6e781df1a6a64e609b10e23969681(CVE-2026-41992)

gzip is a single-file/stream lossless data compression utility, where the resulting compressed file generally has the suffix .gz.

Security Fix(es):

GNU gzip contains a vulnerability in the gzexe utility related to insecure temporary file handling. When the mktemp utility is not available in the user’s PATH, gzexe falls back to constructing a temporary file path based solely on the process ID (PID). This predictable filename is created without exclusive access or existence checks. A local attacker can pre‑create the predicted temporary file path as a symbolic link pointing to an arbitrary file writable by the victim. When gzexe runs, it follows the symlink and overwrites the target file, resulting in a time‑of‑check to time‑of‑use (TOCTOU) condition that allows arbitrary file overwrite.

This issue has been fixed in the commit 4e6f8b24ab823146ab8776f0b7fe486ab34d4269(CVE-2026-41991)

GNU gzip contains a global buffer overflow vulnerability in the LZH decompression logic caused by improper reuse of shared global state between different decompression formats within a single execution. GNU gzip maintains a global array that is shared across the LZ77, LZW, and LZH decompression routines and is not reinitialized between files processed in the same invocation. By decompressing a specially crafted LZW file followed by a specially crafted LZH file in a single gzip -d command, an attacker can poison the shared global state and subsequently trigger an out‑of‑bounds read in the LZH decoder. The LZH decompression logic follows stale values left in the shared array, causing reads past the end of the allocated global buffer.

This issue has been fixed in the commit 63dbf6b3b9e6e781df1a6a64e609b10e23969681(CVE-2026-41992)

gzip is a single-file/stream lossless data compression utility, where the resulting compressed file generally has the suffix .gz.

Security Fix(es):

GNU gzip contains a vulnerability in the gzexe utility related to insecure temporary file handling. When the mktemp utility is not available in the user’s PATH, gzexe falls back to constructing a temporary file path based solely on the process ID (PID). This predictable filename is created without exclusive access or existence checks. A local attacker can pre‑create the predicted temporary file path as a symbolic link pointing to an arbitrary file writable by the victim. When gzexe runs, it follows the symlink and overwrites the target file, resulting in a time‑of‑check to time‑of‑use (TOCTOU) condition that allows arbitrary file overwrite.

This issue has been fixed in the commit 4e6f8b24ab823146ab8776f0b7fe486ab34d4269(CVE-2026-41991)

GNU gzip contains a global buffer overflow vulnerability in the LZH decompression logic caused by improper reuse of shared global state between different decompression formats within a single execution. GNU gzip maintains a global array that is shared across the LZ77, LZW, and LZH decompression routines and is not reinitialized between files processed in the same invocation. By decompressing a specially crafted LZW file followed by a specially crafted LZH file in a single gzip -d command, an attacker can poison the shared global state and subsequently trigger an out‑of‑bounds read in the LZH decoder. The LZH decompression logic follows stale values left in the shared array, causing reads past the end of the allocated global buffer.

This issue has been fixed in the commit 63dbf6b3b9e6e781df1a6a64e609b10e23969681(CVE-2026-41992)

The gzip packages contain the gzip (GNU zip) data compression utility. gzip is used to compress regular files. It replaces them with files containing the .gz extension, while retaining ownership modes, access, and modification times.

Security Fix(es):

• gzip: gzip: Arbitrary file overwrite via insecure temporary file handling in gzexe utility (CVE-2026-41991)

• gzip: gzip: Information disclosure via global buffer overflow in LZH decompression (CVE-2026-41992)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

The gzip packages contain the gzip (GNU zip) data compression utility. gzip is used to compress regular files. It replaces them with files containing the .gz extension, while retaining ownership modes, access, and modification times.

Security Fix(es):

• gzip: gzip: Arbitrary file overwrite via insecure temporary file handling in gzexe utility (CVE-2026-41991)

• gzip: gzip: Information disclosure via global buffer overflow in LZH decompression (CVE-2026-41992)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

The gzip packages contain the gzip (GNU zip) data compression utility. gzip is used to compress regular files. It replaces them with files containing the .gz extension, while retaining ownership modes, access, and modification times.

Security Fix(es):

• gzip: gzip: Arbitrary file overwrite via insecure temporary file handling in gzexe utility (CVE-2026-41991)

• gzip: gzip: Information disclosure via global buffer overflow in LZH decompression (CVE-2026-41992)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

GNU gzip contains a vulnerability in the gzexe utility related to insecure temporary file handling. When the mktemp utility is not available in the user’s PATH, gzexe falls back to constructing a temporary file path based solely on the process ID (PID). This predictable filename is created without exclusive access or existence checks. A local attacker can pre‑create the predicted temporary file path as a symbolic link pointing to an arbitrary file writable by the victim. When gzexe runs, it follows the symlink and overwrites the target file, resulting in a time‑of‑check to time‑of‑use (TOCTOU) condition that allows arbitrary file overwrite. This issue has been fixed in the commit 4e6f8b24ab823146ab8776f0b7fe486ab34d4269

The gzip packages contain the gzip (GNU zip) data compression utility. gzip is used to compress regular files. It replaces them with files containing the .gz extension, while retaining ownership modes, access, and modification times.

Security Fix(es):

• gzip: gzip: Arbitrary file overwrite via insecure temporary file handling in gzexe utility (CVE-2026-41991)
• gzip: gzip: Information disclosure via global buffer overflow in LZH decompression (CVE-2026-41992)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

The gzip packages contain the gzip (GNU zip) data compression utility. gzip is used to compress regular files. It replaces them with files containing the .gz extension, while retaining ownership modes, access, and modification times.

Security Fix(es):

• gzip: gzip: Arbitrary file overwrite via insecure temporary file handling in gzexe utility (CVE-2026-41991)
• gzip: gzip: Information disclosure via global buffer overflow in LZH decompression (CVE-2026-41992)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

The gzip packages contain the gzip (GNU zip) data compression utility. gzip is used to compress regular files. It replaces them with files containing the .gz extension, while retaining ownership modes, access, and modification times.

Security Fix(es):

• gzip: gzip: Arbitrary file overwrite via insecure temporary file handling in gzexe utility (CVE-2026-41991)
• gzip: gzip: Information disclosure via global buffer overflow in LZH decompression (CVE-2026-41992)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

• CVE-2026-41991: fix a race when creating a temporary file in gzexe and zdiff on platforms lacking mktemp

• CVE-2026-41991: fix a race when creating a temporary file in gzexe and zdiff on platforms lacking mktemp

The updated package fixes security vulnerabilities: Predictable Temporary File in GNU gzip. (CVE-2026-41991) Global Buffer Overflow in GNU gzip. (CVE-2026-41992)

These are all security issues fixed in the gzip-1.14-2.1 package on the GA media of openSUSE Tumbleweed.

This update for gzip fixes the following issue

• CVE-2026-41991: insecure temporary file handling in the gzexe utility when the mktemp utility is not available in the user's PATH (bsc#1269622).

Root has patched CVE-2026-41991 in the gzip package for Root:Debian:11. Multiple fixed versions available.

Root has patched CVE-2026-41991 in the gzip package for Root:Debian:12. Multiple fixed versions available.

Root has patched CVE-2026-41991 in the gzip package for Root:Debian:13. Multiple fixed versions available.

This update for gzip fixes the following issue

• CVE-2026-41991: insecure temporary file handling in the gzexe utility when the mktemp utility is not available in the user's PATH (bsc#1269622).

This update for gzip fixes the following issue

• CVE-2026-41991: insecure temporary file handling in the gzexe utility when the mktemp utility is not available in the user's PATH (bsc#1269622).

This update for gzip fixes the following issue

• CVE-2026-41991: insecure temporary file handling in the gzexe utility when the mktemp utility is not available in a user's PATH (bsc#1269622).

This update for gzip fixes the following issue

• CVE-2026-41991: insecure temporary file handling in the gzexe utility when the mktemp utility is not available in a user's PATH (bsc#1269622).

This update for gzip fixes the following issue:

• CVE-2026-41991: insecure temporary file handling in the gzexe utility when the mktemp utility is not available in the user's PATH (bsc#1269622).

This update for gzip fixes the following issue:

• CVE-2026-41991: insecure temporary file handling in the gzexe utility when the mktemp utility is not available in the user's PATH (bsc#1269622).

It was discovered that Gzip's gzexe utility handled temporary files in an insecure manner. When the mktemp utility was not available, gzexe constructed a temporary file path based on the process ID, which could be predicted. A local attacker could possibly use this issue to overwrite arbitrary files via a symlink attack. (CVE-2026-41991)

It was discovered that Gzip incorrectly handled certain compressed files. An attacker could possibly use this issue to obtain sensitive information or cause Gzip to crash, resulting in a denial of service. (CVE-2026-41992)

Michał Majchrowicz and Marcin Wyczechowski discovered that Gzip's gzexe utility created temporary files in an insecure manner when mktemp was unavailable. A local attacker could possibly use this issue to overwrite arbitrary files. (CVE-2026-41991)

Elias Hasas, Michał Majchrowicz and Marcin Wyczechowski discovered that Gzip incorrectly handled certain compressed files. An attacker could possibly use this issue to obtain sensitive information or cause Gzip to crash, resulting in a denial of service. (CVE-2026-41992)

USN-8733-1 fixed vulnerabilities in Gzip. This update provides the corresponding fix for Gzip on Ubuntu 14.04 LTS, Ubuntu 18.04 LTS and Ubuntu 20.04 LTS.

Original advisory details:

Michał Majchrowicz and Marcin Wyczechowski discovered that Gzip's gzexe utility created temporary files in an insecure manner when mktemp was unavailable. A local attacker could possibly use this issue to overwrite arbitrary files. (CVE-2026-41991)

Elias Hasas, Michał Majchrowicz and Marcin Wyczechowski discovered that Gzip incorrectly handled certain compressed files. An attacker could possibly use this issue to obtain sensitive information or cause Gzip to crash, resulting in a denial of service. (CVE-2026-41992)