Raw vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:HSummary
CVE-2025-21799 is a medium-severity NULL Pointer Dereference (CWE-476) vulnerability in Linux Linux Kernel. Its CVSS base score is 5.5 (Medium).
Operationally, ranked at the 13th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified map to SI-10 (Information Input Validation) and SI-11 (Error Handling) — see the control section below for these in your framework.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2025-5990
Vulnerability Data
In the Linux kernel, the following vulnerability has been resolved: net: ethernet: ti: am65-cpsw: fix freeing IRQ in am65_cpsw_nuss_remove_tx_chns() When getting the IRQ we use k3_udma_glue_tx_get_irq() which returns negative error value on error. So not NULL check is not sufficient…
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to deteremine if IRQ is valid. Check that IRQ is greater then zero to ensure it is valid. There is no issue at probe time but at runtime user can invoke .set_channels which results in the following call chain. am65_cpsw_set_channels() am65_cpsw_nuss_update_tx_rx_chns() am65_cpsw_nuss_remove_tx_chns() am65_cpsw_nuss_init_tx_chns() At this point if am65_cpsw_nuss_init_tx_chns() fails due to k3_udma_glue_tx_get_irq() then tx_chn->irq will be set to a negative value. Then, at subsequent .set_channels with higher channel count we will attempt to free an invalid IRQ in am65_cpsw_nuss_remove_tx_chns() leading to a kernel warning. The issue is present in the original commit that introduced this driver, although there, am65_cpsw_nuss_update_tx_rx_chns() existed as am65_cpsw_nuss_update_tx_chns().
- CWE(s)
Related Threats
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
Mitigating Controls (NIST 800-53 r5) AI
Directly requires validation of the k3_udma_glue_tx_get_irq() return value (must be >0) before storing or later using tx_chn->irq, eliminating the invalid-IRQ path.
Mandates correct handling of error returns from k3_udma_glue_tx_get_irq() so that a negative value never reaches the free-IRQ logic in am65_cpsw_nuss_remove_tx_chns().
Requires timely application of the kernel patch that replaces the insufficient NULL check with a >0 check, closing the exact flaw described in the CVE.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Secure SDLC practices (static analysis, code review, safe coding standards) directly prevent NULL dereference bugs during development.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Security testing can detect NULL dereference defects before release.
Secure SDLC mandates defensive coding practices that can prevent NULL dereferences.
Application security requirements can specify input validation and pointer-safety rules.
Secure architecture principles encourage defensive design that avoids unsafe pointer use.
Secure coding standards directly require NULL-pointer checks and safe dereference patterns.