Ubuntu issues ten security notices in four days fixing flaws in PHP, Perl, FFmpeg, curl, ImageMagick, Netty, Python and Apache

Perl versions through 5.45.1 have out-of-bounds heap reads and writes during regular expression matching via an undersized superlinear cache in S_regmatch. The regex engine's superlinear cache holds one bit per subject position for each participating WHILEM node, so the bit count is the subject length plus one times the number of nodes. Nothing checks that product for positive overflow of the signed 32-bit count: a 286331153 byte subject matched against a pattern with 15 participating nodes stores the count as 14, leaving a two byte cache. The cache is then indexed from the real match position and node number, so reads go past the end of the allocation, and on failure CACHEsayNO sets a bit past it. A caller that matches an attacker controlled subject of this size against a pattern of this shape can crash the process or corrupt heap memory.

Attacker-provided inputs to bccomp() could lead to an out-of-bounds write with stack and heap corruption in PHP versions from 8.4.* before 8.4.24 and from 8.5.* before 8.5.9.

Perl versions from 5.9.4 before 5.41.9 can produce incorrect regular-expression match results because a stale failure flag in the Aho-Corasick prescan (S_find_byclass) is not cleared when a later transition succeeds, causing the prescan to stop before it records an earlier valid match position. The flaw is triggered by alternation patterns where one candidate position is recorded and a later character then forces a fallback through a fail link that succeeds; for example, 'ABCDE' =~ m/ABCF|BCDE|C/ matches C at offset 2 instead of BCDE, and m/ABCF|BCDE|C(G/) fails to match at all. An attacker who controls input to such a regex can make an access-control, validation, or filtering decision resolve incorrectly, either matching the wrong alternative branch or missing a match entirely, with impact rated low (CVSS 5.3, medium). Any application running an affected Perl interpreter whose security-relevant regexes use alternations is exposed, and because Perl ships by default with virtually all Linux and Unix systems the installed base is enormous even though only specific pattern shapes trigger the bug. No public proof-of-concept is known, the issue is not in CISA KEV, and EPSS puts the 30-day exploitation probability at 0.4%, so no exploitation is currently known.

Do: Upgrade to Perl 5.41.9 or later, or apply vendor backports such as Ubuntu's USN-8736-1 for affected distribution packages. Audit regex-based access-control, validation, and filtering rules that use alternations, and test them against inputs where a later alternative should match after an earlier one fails. No reliable workaround exists because the defect is inside the regex engine itself, so patching is the primary remediation.

A NULL pointer dereference in the mod_authn_socache in Apache HTTP Server 2.4.66 and earlier allows an unauthenticated remote user to crash a child process in a caching forward proxy configuration. Users are recommended to upgrade to version 2.4.67, which fixes this issue.

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().

ImageMagick before 7.1.2-15 contains a use-after-free vulnerability in the PDB decoder that uses a stale pointer when memory allocation fails. Attackers can trigger this vulnerability by processing malicious PDB files to cause crashes or write a single zero byte to freed memory.

ImageMagick before 7.1.2-15 contains a memory leak vulnerability in multiple coders that write raw pixel data where allocated objects are not properly freed. Attackers can trigger this leak by processing specially crafted images, causing memory exhaustion and denial of service.

ImageMagick before 7.1.2-15 and 6.9.13-40 contains a memory leak in coders/txt.c when processing TXT files with texture attributes: the texture object allocated via ReadImage is not released when GetTypeMetrics fails, leaking memory each time a crafted TXT file with a texture attribute is processed.

CVE-2026-58649 is an origin validation error (CWE-346) in Microsoft's .NET platform, meaning the runtime fails to correctly verify the origin of network requests, allowing an unauthenticated attacker to trigger an information-disclosure condition. The CVSS vector (AV:N/AC:L/PR:N/UI:R) indicates the flaw is reachable over a network with low attack complexity and no privileges required, but a victim user must interact with attacker-influenced content for it to fire. A successful attacker gains access to confidential information handled by the affected application (confidentiality impact rated High), with no integrity or availability impact. Any organization running supported .NET deployments that have not yet received the September 2026 Patch Tuesday updates is potentially affected. There is currently no public proof-of-concept, the flaw is not in CISA's KEV, and EPSS puts 30-day exploitation probability at just 0.3%, so no in-the-wild exploitation is known.

Do: Apply Microsoft's September 2026 .NET security updates as part of this month's Patch Tuesday rollout, and check Microsoft's advisory for the exact version ranges that need upgrading. Prioritize internet-facing .NET/ASP.NET applications that perform cross-origin request handling, and review their origin-verification (CORS) configuration as an interim risk reduction. Because exploitation requires user interaction, also treat user-facing lure links as part of the realistic attack path until systems are patched.

FFmpeg versions 8.0 through 8.1.2 contains a stack buffer overflow vulnerability in the Vulkan HEVC hardware decoder that allows remote attackers to overwrite return addresses and adjacent stack frames by supplying a crafted HEVC/H.265 bitstream. Attackers can embed a malicious vps_num_hrd_parameters value exceeding HEVC_MAX_SUB_LAYERS in any supported container format to overflow stack-allocated arrays in the vk_hevc_end_frame function, potentially achieving arbitrary code execution.

FFmpeg through 8.1.2, fixed in commit aafb5c6, contains a signed integer overflow vulnerability in the MACE6 audio decoder that allows attackers to corrupt heap memory by supplying a crafted CAF file with a malicious bytes_per_packet value. Attackers can craft a CAF file with oversized bytes_per_packet and frames_per_packet values in the desc chunk to trigger an integer overflow in mace_decode_frame() during output sample count computation, resulting in an undersized buffer allocation and heap out-of-bounds write that could enable code execution.

CVE-2026-69806 is an information-exposure flaw in Microsoft .NET (CWE-200, with an associated code-generation issue, CWE-94) that allows an authorized actor to elevate privileges locally. To trigger it, an attacker must already hold a low-privileged foothold on the target system — such as the ability to execute code as a standard local user — and the high-complexity local attack path requires no user interaction. A successful exploit carries high-impact confidentiality, integrity, and availability consequences, effectively yielding elevation of privilege on the affected host. Any organization running the affected .NET components on Windows clients or servers is in scope, and the fix shipped in Microsoft's September 2026 Patch Tuesday (September 8, 2026), part of a record 966-flaw release. There is no public proof-of-concept, the flaw is not in CISA KEV, and no in-the-wild exploitation is known; EPSS assigns a 1.8% probability of exploitation within 30 days (77th percentile).

Do: Apply the .NET updates released with the September 2026 Patch Tuesday set via Windows Update, WSUS, or the Microsoft Update Catalog, verifying both .NET Framework and modern .NET runtimes against Microsoft's advisory for exact affected version ranges. Prioritize multi-user systems where standard users can already run code — RDS/terminal hosts, build and CI servers, and shared workstations — since the attack requires local access. No workaround is described in the available data, so patching is the primary mitigation.

In PHP versions 8.2.* before 8.2.31, 8.3.* before 8.3.31, 8.4.* before 8.4.21, and 8.5.* before 8.5.6, the metaphone() function in ext/standard/metaphone.c uses a signed int variable to track the current position within the input string. If a string longer than 2,147,483,647 bytes is passed, a signed integer overflow occurs, resulting in undefined behavior. This can lead to an out-of-bounds read, causing a segmentation fault or access to unrelated memory, and may affect the availability of the PHP process.