Linux: Missing Release of Memory after Effective Lifetime
CVE-2026-46303 is a high-severity missing release of memory after effective lifetime vulnerability in Linux, with a CVSS 3.1 base score of 8.2 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists versions 8356fb821016797f5677cbeee5ddc0d32a95b4be, d582e12378bc1637f337622feef762f53c43fd57, bf1bc673c587f5ef7e9c09b94aea7c5a7847d4d9 as the first without the flaw, so updating Linux to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.32% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Linux to 8356fb821016797f5677cbeee5ddc0d32a95b4be or d582e12378bc1637f337622feef762f53c43fd57 or bf1bc673c587f5ef7e9c09b94aea7c5a7847d4d9 or c9b37c8b73f6368e4750e5ccb0632c380b43c6e5, whichever matches your release line, or a later version.
- Update Linux Kernel to 2.6.33 or 3.3 or 3.5 or 3.11, whichever matches your release line, or a later version.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | f54e18f1b831c92f6512d2eedb224cd63d607d3d up to, but not including, 8356fb821016797f5677cbeee5ddc0d32a95b4be; f54e18f1b831c92f6512d2eedb224cd63d607d3d up to, but not including, d582e12378bc1637f337622feef762f53c43fd57; f54e18f1b831c92f6512d2eedb224cd63d607d3d up to, but not including, bf1bc673c587f5ef7e9c09b94aea7c5a7847d4d9; f54e18f1b831c92f6512d2eedb224cd63d607d3d up to, but not including, c9b37c8b73f6368e4750e5ccb0632c380b43c6e5; f54e18f1b831c92f6512d2eedb224cd63d607d3d up to, but not including, 22b36fa081f38ab397c7697f9d539211b51a0cfc; f54e18f1b831c92f6512d2eedb224cd63d607d3d up to, but not including, e69da8eeab74b4f4505024c38a17bce060fe7df8; f54e18f1b831c92f6512d2eedb224cd63d607d3d up to, but not including, ef048470c90bc8c1b8318bb2ce329da9ef64b9fe; f54e18f1b831c92f6512d2eedb224cd63d607d3d up to, but not including, a36d990f591320e9dd379ab30063ebfe91d47e1f; and 17 more ranges | 8356fb821016797f5677cbeee5ddc0d32a95b4be, d582e12378bc1637f337622feef762f53c43fd57, bf1bc673c587f5ef7e9c09b94aea7c5a7847d4d9, c9b37c8b73f6368e4750e5ccb0632c380b43c6e5, 22b36fa081f38ab397c7697f9d539211b51a0cfc, e69da8eeab74b4f4505024c38a17bce060fe7df8 |
| Siemens | SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0) | V3.1.6 and later; V3.1.7 and later | Not stated |
| Siemens | SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0) | V3.1.6 and later; V3.1.7 and later | Not stated |
| Siemens | SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0) | V3.1.6 and later; V3.1.7 and later | Not stated |
| Siemens | SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AC0) | V3.1.6 and later; V3.1.7 and later | Not stated |
| Siemens | SIMATIC S7-1500 TM MFP - GNU/Linux subsystem | all versions | Not stated |
| Siemens | SIPLUS S7-1500 CPU 1518-4 PN/DP MFP (6AG1518-4AX00-4AC0) | V3.1.6 and later; V3.1.7 and later | Not stated |
| Linux | Linux Kernel | 2.6.32.66 up to, but not including, 2.6.33; 3.2.67 up to, but not including, 3.3; 3.4.107 up to, but not including, 3.5; 3.10.64 up to, but not including, 3.11; 3.12.36 up to, but not including, 3.13; 3.14.28 up to, but not including, 3.15; 3.17.8 up to, but not including, 3.18; 3.18.2 up to, but not including, 5.10.258; and 7 more ranges | 2.6.33, 3.3, 3.5, 3.11, 3.13, 3.15 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- LowLimited modification of data is possible.
- Availability
- NoneAvailability is not affected.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N. Scored by CNA.
Official description
In the Linux kernel, the following vulnerability has been resolved: isofs: validate Rock Ridge CE continuation extent against volume size rock_continue() reads rs->cont_extent verbatim from the Rock Ridge CE record and passes it to sb_bread() without checking that the block number is within the mounted ISO 9660 volume. commit e595447e177b ("[PATCH] rock.c: handle corrupted directories") added cont_offset and cont_size rejection for the CE continuation but did not validate the extent block number itself. commit f54e18f1b831 ("isofs: Fix infinite looping over CE entries") later capped the CE chain length at RR_MAX_CE_ENTRIES = 32 but again left the block number unchecked. With a crafted ISO mounted via udisks2 (desktop optical auto-mount) or via CAP_SYS_ADMIN mount, rs->cont_extent can therefore point at an out-of-range block or at blocks belonging to an adjacent filesystem on the same block device. sb_bread() on an out-of-range block returns NULL cleanly via the block layer EIO path, so there is no memory-safety violation. For in-range reads of adjacent- filesystem data, the CE buffer is parsed as Rock Ridge records and only the text of SL sub-records reaches userspace through readlink(), which makes the info-leak channel narrow and difficult to exploit; still, rejecting the malformed CE outright matches the rejection shape already present in the same function for cont_offset and cont_size. Add an ISOFS_SB(sb)->s_nzones bounds check to rock_continue() next to the existing offset/size rejection, printing the same corrupted-directory-entry notice.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Missing Release of Memory after Effective Lifetime
The product does not sufficiently track and release allocated memory after it has been used, making the memory unavailable for reallocation and reuse.
How developers prevent this class of flaw
- Choose a language or tool that provides automatic memory management, or makes manual memory management less error-prone. For example, glibc in Linux provides protection against free of invalid pointers. When using Xcode to target OS X or iOS, enable automatic reference counting (ARC). To help correctly and consistently manage memory when programming in C++, consider using a smart pointer class such as std
- Use an abstraction library to abstract away risky APIs. Not a complete solution.
- Consider using the Boehm-Demers-Weiser garbage collector (bdwgc), which can help avoid leaks.
More Missing Release of Memory after Effective Lifetime vulnerabilities (CWE-401)
Timeline
- CVE record published.
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
- git.kernel.org/stable/c/22b36fa081f38ab397c7697f9d539211b51a0cfc
- git.kernel.org/stable/c/8356fb821016797f5677cbeee5ddc0d32a95b4be
- git.kernel.org/stable/c/a36d990f591320e9dd379ab30063ebfe91d47e1f
- git.kernel.org/stable/c/bf1bc673c587f5ef7e9c09b94aea7c5a7847d4d9
- git.kernel.org/stable/c/c9b37c8b73f6368e4750e5ccb0632c380b43c6e5
- git.kernel.org/stable/c/d582e12378bc1637f337622feef762f53c43fd57
- git.kernel.org/stable/c/e69da8eeab74b4f4505024c38a17bce060fe7df8
- git.kernel.org/stable/c/ef048470c90bc8c1b8318bb2ce329da9ef64b9fe
Other references
Recent Missing Release of Memory after Effective Lifetime vulnerabilities
- 7.0 High severity
- 9.8 Critical severity
- 7.8 High severity
- 7.8 High severity
- 7.5 High severity
- 7.5 High severity
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