GHSA-7f92-rr6w-cq64 CVE-2021-48018
Storage corruption due to variables overwritten by re-entrancy locks
High
PyPI
- Severity
- 8.3 / 10
- High · CVSS 4.0
- Exploit chance (EPSS)
- 0.39%
- Chance of exploitation in the next 30 days. Higher than 33.29% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- CWE-787 Out-of-bounds Write
- Fix
0.2.15- Upgrade vyper to this version or later
Description
Background
When attempting to use the v0.2.14 release, @pandadefi discovered an issue using the @nonreentrant decorator.
Impact
Reentrancy protection storage slots get allocated to the same slots as storage variables, leading to the corruption of storage variables when using the @nonreentrant decorator.
Patches
This issue was fixed in v0.2.15 in #2391, #2379
Workarounds
Don't use the @nonreentrant decorator in these versions.
Affected versions
PyPI
| Package | Vulnerable | Fixed in |
|---|---|---|
| vyper | >= 0.2.13, < 0.2.15 |
0.2.15 |
How to fix
Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.
vyper PyPI → 0.2.15
- pip
pip install --upgrade "vyper>=0.2.15"- poetry
poetry add "vyper>=0.2.15"- uv
uv add "vyper>=0.2.15"
Severity breakdown
CVSS 4.0 8.3
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
- Attack vector
- Network
- Attack complexity
- Low
- Attack requirements
- Present
- Privileges required
- None
- User interaction
- None
- Confidentiality (vulnerable system)
- None
- Integrity (vulnerable system)
- High
- Availability (vulnerable system)
- High
- Confidentiality (subsequent systems)
- None
- Integrity (subsequent systems)
- None
- Availability (subsequent systems)
- None
- Exploit maturity
- Not defined
- Scope
- X
CVSS 3.1 7.4
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:H
- Attack vector
- Network
- Attack complexity
- High
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- High
- Availability
- High
Weakness
CWE-787: Out-of-bounds Write
The product writes data past the end, or before the beginning, of the intended buffer.
How to prevent it
- Requirements: Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, many languages that perform their own memory management, such as Java and Perl, are not subject to buffer overflows. Other languages, such as Ada and C#, typically provide overflow protection, but the protection can be disabled by the programmer. Be wary that a language's interface to native code may still be subject to overflows, even if the language itself is theoretically safe.
- Architecture and Design: Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. Examples include the Safe C String Library (SafeStr) by Messier and Viega [REF-57], and the Strsafe.h library from Microsoft [REF-56]. These libraries provide safer versions of overflow-prone string-handling functions.
- Operation, Build and Compilation: Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index checking. D3-SFCV (Stack Frame Canary Validation) from D3FEND [REF-1334] discusses canary-based detection in detail.
- Implementation: Consider adhering to the following rules when allocating and managing an application's memory: Double check that the buffer is as large as specified. When using functions that accept a number of bytes to copy, such as strncpy(), be aware that if the destination buffer size is equal to the source buffer size, it may not NULL-terminate the string. Check buffer boundaries if accessing the buffer in a loop and make sure there is no danger of writing past the allocated space. If necessary, truncate all input strings to a reasonable length before passing them to the copy and concatenation functions.
- Operation, Build and Compilation: Run or compile the software using features or extensions that randomly arrange the positions of a program's executable and libraries in memory. Because this makes the addresses unpredictable, it can prevent an attacker from reliably jumping to exploitable code. Examples include Address Space Layout Randomization (ASLR) [REF-58] [REF-60] and Position-Independent Executables (PIE) [REF-64]. Imported modules may be similarly realigned if their default memory addresses conflict with other modules, in a process known as "rebasing" (for Windows) and "prelinking" (for Linux) [REF-1332] using randomly generated addresses. ASLR for libraries cannot be used in conjunction with prelink since it would require relocating the libraries at run-time, defeating the whole purpose of prelinking. For more information on these techniques see D3-SAOR (Segment Address Offset Randomization) from D3FEND [REF-1335].
- Operation: Use a CPU and operating system that offers Data Execution Protection (using hardware NX or XD bits) or the equivalent techniques that simulate this feature in software, such as PaX [REF-60] [REF-61]. These techniques ensure that any instruction executed is exclusively at a memory address that is part of the code segment. For more information on these techniques see D3-PSEP (Process Segment Execution Prevention) from D3FEND [REF-1336].
- Implementation: Replace unbounded copy functions with analogous functions that support length arguments, such as strcpy with strncpy. Create these if they are not available.
References
Other links
Timeline
- Published
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| GHSA-2r3x-4mrv-mcxf Vyper: Memory corruption using function calls within tuples / nested calls | Medium | Also affects vyper |
| GHSA-4v7v-gqf9-ww2g Vyper: Call stack corruption when passing complex type containing non-base type members as argument | Medium | Also affects vyper |
| GHSA-vg88-3v92-rjx2 Vyper: Return inside for loop more than 1 level deep | Low | Also affects vyper |
| GHSA-3vcg-j39x-cwfm Vyper's `slice()` may elide side-effects when output length is 0 | Low | Also affects vyper |
| GHSA-qhr6-mgqr-mchm Vyper's `concat()` builtin may elide side-effects for zero-length arguments | Low | Also affects vyper |
| GHSA-h33q-mhmp-8p67 Vyper has a double eval in For List Iter | High | Also affects vyper |
| GHSA-4w26-8p97-f4jp AugAssign evaluation order causing OOB write within the object in Vyper | Critical | Also affects vyper |
| GHSA-2p94-8669-xg86 Vyper's sqrt doesn't define rounding behavior | High | Also affects vyper |
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