Summary
In the Linux kernel, the following vulnerability has been resolved: riscv: fix runtime constant...
In the Linux kernel, the following vulnerability has been resolved:
riscv: fix runtime constant support for nommu kernels
the __runtime_fixup_32 function does not handle the case where val is
zero correctly (as might occur when patching a nommu kernel and referring
to a physical address below the 4GiB boundary whose upper 32 bits are all
zero) because nothing in the existing logic prevents the code from taking
the else branch of both nop-checks and emitting two nop instructions.
This leaves random garbage in the register that is supposed to receive the
upper 32 bits of the pointer instead of zero that when combined with the
value for the lower 32 bits yields an invalid pointer and causes a kernel
panic when that pointer is eventually accessed.
The author clearly considered the fact that if the lui is converted into
a nop that the second instruction needs to be adjusted to become an li
instead of an addi, hence introducing the addi_insn_mask variable, but
didn't follow that logic through fully to the case where the else branch
executes. To fix it just adjust the logic to ensure that the second else
branch is not taken if the first instruction will be patched to a nop.
Impact
The application dereferences a null pointer, causing a crash. Typical impact: denial of service via crash.
CVE-2025-38433 has a CVSS score of 5.5 (Medium). The vector is requires local access, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. No fixed version is listed yet, so configuration controls and monitoring matter more in the interim.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Frequently Asked Questions
- What is CVE-2025-38433? CVE-2025-38433 is a medium-severity null pointer dereference vulnerability. No fixed version is listed yet. The application dereferences a null pointer, causing a crash.
- How severe is CVE-2025-38433? CVE-2025-38433 has a CVSS score of 5.5 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Is there a fix for CVE-2025-38433? No fixed version is listed for CVE-2025-38433 yet. Monitor the advisory for updates and apply mitigations in the interim.
- Is CVE-2025-38433 exploitable, and should I be worried? Whether CVE-2025-38433 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2025-38433 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.